Inflatable devices for separating layers of tissue and methods of using

ABSTRACT

An apparatus and method for separating a first layer of tissue from a second layer of tissue. A supporting part extends into the interior of the balloon during inflation to provide support for the balloon. The supporting part is retracted to a position outside the interior of the balloon after inflating the balloon. An endoscope is then inserted into the interior of the balloon. The endoscope is moved within the interior of the balloon to change the field of view of the endoscope.

This is a continuation of application Ser. No. 08/365,096 filed on Dec.28, 1994, now abandoned, which is a continuation in part of Ser. No.08/319,552, filed Oct. 7, 1994 of inventors Albert K. Chin, Jeffrey A.Smith, John P. Lunsford and Frederic H. Moll now U.S. Pat. No.5,643,310, which is a continuation in part of Ser. No. 08/282,287, filedJul. 29, 1994 of inventors Frederic H. Moll, Jeff Smith, John P.Lunsford and Albert K. Chin, now abandoned, which is aContinuation-in-Part of application Ser. No. 911,714, filed Jul. 10,1992, of inventors Albert K. Chin and John P. Lunsford, which is aContinuation-in-Part of application Ser. No. 794,590, filed 19 Nov.1991, now issued as U.S. Pat. No. 5,309,896, of inventors Frederic H.Moll, Charles Gresl, Jr., Albert K. Chin, and Philip K. Hopper, which isa Continuation-in-Part of application Ser. No. 706,781, filed 29 May1991, now abandoned, of inventors Frederic H. Moll, Albert K. Chin,Diane E. Caramore, and Frank T. Watkins III.

BACKGROUND OF THE INVENTION

The present invention relates to the field of inflatable tissueseparation devices and methods of using such devices. The apparatus andmethods of the present invention may be used in any procedure requiringdissection and/or retraction of tissue planes throughout the bodyincluding inguinal hernia repair, pelvic lymphadenectomy and bladderneck suspension in the preperitoneal space; renal, adrenal, aortic andanterior spinal access in the retroperitoneal space; penile prostheticreservoir placement in the anterior abdominal wall; and augmentationmammaplasty prosthetic placement. By way of example only, use of suchdevices and methods for hernia repair will be described.

A hernia is the protrusion of part of a body part or structure through adefect in the wall of a surrounding structure. Most commonly, a herniais the protrusion of part of abdominal contents, including bowel,through a tear or weakness in the abdominal wall, or through theinguinal canal into the scrotum.

An abdominal hernia is repaired by suturing or stapling a mesh patchover the site of the tear or weakness. The mesh patch has a roughsurface that can irritate the bowel and cause adhesions. It is thereforepreferred to install the patch properitoneally. It is intended that theterms properitoneal and preperitoneal be synonymous. The mesh patch ispreferably attached to the properitoneal fascia of the abdominal wall,and covered by the peritoneum. To attach the mesh patch to theproperitoneal fascia, the peritoneum must be dissected from theproperitoneal fascia. This is a difficult process which involves therisk of puncturing the peritoneum. Moreover, strands of properitonealfat interconnecting the peritoneum and the properitoneal fascia make itdifficult to see the site of the hernia.

The use of laparoscopic techniques to perform hernia repair is becomingincreasingly common. In the conventional procedure for carrying out ahernia repair laparoscopically, an endoscope and instruments areintroduced into the belly through one or more incisions in the abdominalwall, and are advanced through the belly to the site of the hernia.Then, working from inside the belly, a long incision is made in theperitoneum covering the site of the hernia. Part of the peritoneum isdissected from the properitoneal fat layer to provide access to the fatlayer. This is conventionally done by blunt dissection, such as bysweeping a rigid probe under the peritoneum. In this procedure, it isdifficult to dissect the peritoneum cleanly since patchy layers ofproperitoneal fat tend to adhere to the peritoneum.

In an alternative known laparoscopic hernia repair procedure, the bellyis insufflated. An incision is made in the abdominal wall close to thesite of the hernia. The incision is made through the abdominal wall asfar as the properitoneal fat layer. The peritoneum is then bluntdissected from the properitoneal fat layer by passing a finger or arigid probe through the incision and sweeping the finger or rigid probeunder the peritoneum. After the peritoneum is dissected from theproperitoneal fat layer, the space between the peritoneum and theproperitoneal fat layer is insufflated to provide a working space inwhich to apply the mesh patch to the properitoneal fascia.

During the blunt dissection process, it is easy to puncture through theperitoneum, which is quite thin. Additionally, after initial dissectionof the properitoneal space, known surgical procedures requireintroduction of various instruments in the space to conduct the surgery.These instruments can cause inadvertent puncture of the peritoneum wallafter the initial dissection. A puncture destroys the ability of thespace between the peritoneum and the fascia to hold gas insufflation;pressurized gas can travel through a puncture in the peritoneum to allowthe fluid to migrate to the abdominal cavity and degrade the pressuredifferential maintaining the properitoneal cavity. Also, it is difficultto dissect the peritoneum cleanly since patchy layers of properitonealfat tend to adhere to the peritoneum. Clearing difficult adhesions cansometimes result in a breach of the peritoneum itself.

U.S. Pat. No. 5,309,896, of which this application is aContinuation-in-Part, discloses a laparoscopic hernia repair techniquethat enables a mesh patch to be attached to the properitoneal fasciawithout breaching the peritoneum. An incision is made through theabdominal wall as far as the properitoneal fat layer. A multichamberedinflatable retraction device is pushed through the incision into contactwith the peritoneum, and is used to separate the peritoneum from theunderlying layers. The main end chamber of the inflatable retractiondevice is then inflated to elongate the inflatable retraction devicetowards the site of the hernia. As it inflates, the inflatableretraction device gently separates the peritoneum from the underlyinglayers. Once the main chamber of the inflatable retraction device isfully inflated, a second inflatable chamber is inflated. The secondinflatable chamber enables the inflatable retraction device to continueto separate the peritoneum from the underlying layers after the maininflatable chamber has been deflated.

One or more apertures are then cut in the envelope of the maininflatable chamber to provide access to the site of the hernia forinstruments passed into the main chamber. With such an arrangement,instruments pass through the main chamber situated between theperitoneum and the underlying layers. In this way, a patch can beattached to the properitoneal fascia without breaching the peritoneum.

Another device for separating tissue layers is disclosed in U.S. patentapplication Ser. No. 07/911,714, of which this application is acontinuation-in-part. The apparatus includes a main envelope thatdefines a main inflatable chamber. The apparatus also includes anintroducing device for introducing the main envelope in a collapsedstate between the first layer of tissue and the second layer of tissue.The introducing device inflates the main envelope into an expanded stateto separate the first layer of tissue from the second layer of tissue,and to create a working space between the first layer of tissue and thesecond layer of tissue. Finally, the apparatus includes an insufflatingdevice for introducing insufflation gas into the working space betweenthe first layer of tissue and the second layer of tissue.

In a method according to U.S. patent application Ser. No. 07/911,714 ofseparating a first layer of tissue from a second layer of tissue, a mainenvelope and insufflation gas are provided. The main envelope defines amain inflatable chamber. The main envelope is introduced in a collapsedstate between the first layer of tissue and the second layer of tissue.The main envelope is inflated into an expanded state to separate thefirst layer of tissue from the second layer of tissue, and to create aworking space between the first layer of tissue and the second layer oftissue. Finally, insufflation gas is introduced into the working spacebetween the first layer of tissue and the second layer of tissue.

In a first practical embodiment of an apparatus according to U.S. patentapplication Ser. No. 07/911,714, the main envelope and the introducingdevice constitute a first component that separates the first layer oftissue from the second layer of tissue to create the working space. Theinsufflation device constitutes a second component, which insufflatesthe working space to maintain the separation of the first layer oftissue from the second. The insufflation device is tubular, has ananchor flange slidably mounted on it, and has a toroidal inflatablechamber at its distal end. The anchor flange and toroidal inflatablechamber together form a gas-tight seal with the second layer of tissue.

In a method according to U.S. patent application Ser. No. 07/911,714 ofusing the two-component apparatus, the introducing device is used topush the main envelope in a collapsed state through an incision throughthe second layer of tissue to place the main envelope between the firstlayer of tissue and the second layer of tissue. The main envelope isthen inflated to gently separate the first layer of tissue from thesecond layer of tissue, and to create a working space between the twolayers of tissue. An endoscope may be passed through the bore of theintroducing device into the main chamber to observe the extent ofseparation of the layers of tissue. The main envelope is then returnedto a collapsed state, and the main envelope and the introducing deviceare removed from the incision.

The insufflating device is inserted into the incision so that its distalend projects into the working space between the two layers of tissue.The toroidal inflatable chamber is inflated into an expanded state. Theanchor flange is slid distally along the insufflating device to compressthe second layer of tissue between it and the expanded toroidalinflatable chamber, and thus to form a gas-tight seal. Insufflating gasis then passed through the insufflating device into the working space tomaintain the separation of the first layer of tissue from the second. Anendoscope may be passed through the bore of the insufflating device intothe working space to observe within the working space.

In a first embodiment of a one-component apparatus according to U.S.patent application Ser. No. 07/911,714, the introducing device is alsoused for returning the main envelope to a collapsed state. A singleelongated tube provides the introducing device and the insufflatingdevice. The main envelope is detachable from the single elongated tube.The single elongated tube has an anchor flange slidably mounted on it,and has a toroidal inflatable chamber at its distal end. The anchorflange and toroidal inflatable chamber together form a gas-tight sealwith the second layer of tissue.

In a method according to U.S. patent application Ser. No. 07/911,714 ofusing the first embodiment of a one-component apparatus to separate afirst layer of tissue from a second layer of tissue, the elongated tubeis used to push the main envelope in a collapsed state through anincision through the second layer of tissue to place the main envelopebetween the first layer of tissue and the second layer of tissue. Themain envelope is then inflated to gently separate the first layer oftissue from the second layer of tissue, and to create a working spacebetween the two layers of tissue. An endoscope may be passed through thebore of the single elongated tube into the main chamber to observe theextent of separation of the layers of tissue. The main envelope is thenreturned to a collapsed state, detached from the elongated tube, andremoved from the working space between the layers of tissue through thebore of the elongated tube.

The toroidal inflatable chamber at the distal end of the elongated tubeis then inflated into an expanded state. The anchor flange is sliddistally along the elongated tube to compress the second layer of tissuebetween it and the expanded toroidal inflatable chamber to form agas-tight seal. Insufflating gas is passed through the elongated tubeinto the working space to maintain the separation of the first andsecond tissue layers. An endoscope may be passed through the bore of thesingle elongated tube into the working space to observe within theworking space.

In a second embodiment of a one-component apparatus according to U.S.patent application Ser. No. 07/911,714, the introducing device is anouter elongated tube, and the insufflating device is an inner elongatedtube mounted in the bore of the outer elongated tube. The proximal endsof the tubes are flexibly coupled together. The main envelope is acylindrical piece of elastomeric material. One end of the main envelopeis everted with respect to the other, and is attached to the distal endof the outer elongated tube. The other end of the main envelope isattached to the distal end of the inner elongated tube. The maininflatable chamber defined by the main envelope is thus substantiallytoroidal. The outer elongated tube has an anchor flange slidably mountedon it. The anchor flange and the main inflatable chamber together form agastight seal with the second layer of tissue.

In a method according to U.S. patent application Ser. No. 07/911,714 ofusing the second embodiment of a one-component apparatus to separate afirst layer of tissue from a second layer of tissue, the outer elongatedtube is used to push the main envelope in a collapsed state through anincision through the second layer of tissue to place the main envelopebetween the first layer of tissue and the second layer of tissue. Themain envelope is then inflated to gently separate the first layer oftissue from the second layer of tissue, and to create working a spacebetween the layers of tissue. An endoscope may be passed through theouter elongated tube into the main chamber to observe the extent ofseparation of the layers of tissue.

The anchor flange is slid distally along the introducing device tube tocompress the second layer of tissue between it and the main inflatablechamber, to form a gas-tight seal. Insufflating gas is then passedthrough the bore of the inner elongated tube and the bore of the mainenvelope into the working space to maintain the separation of the firstlayer of tissue from the second. An endoscope may be passed through thebore of the inner elongated tube and the bore of the main envelope intothe working space to observe within the working space.

In a further method according to U.S. patent application Ser. No.07/911,714, access through the abdominal wall to repair a hernia isprovided. The abdominal wall includes the peritoneum and an underlyinglayer. A main envelope and an insufflation gas are provided. The mainenvelope defines a main inflatable chamber. The main envelope isintroduced in a collapsed state between the peritoneum and theunderlying layer. The main envelope is inflated into an expanded stateto separate the peritoneum from the underlying layer, and to create aworking space between the peritoneum and the underlying layer.Insufflation gas is introduced into the working space, and the hernia isrepaired using an instrument passed into the working space.

In a final method according to U.S. patent application Ser. No.07/911,714, access is provided through the abdominal wall from near theumbilicus to repair a hernia. The abdominal wall includes the peritoneumand an underlying layer. A main envelope and insufflation gas areprovided. The main envelope defines a main inflatable chamber. Anincision is made at the umbilicus through the abdominal wall, includingthe underlying layer, excluding the peritoneum. The main envelope isintroduced in a collapsed state into the incision to bring the mainenvelope into contact with the peritoneum. The main envelope is inflatedinto an expanded state to separate a portion of the peritoneum from theunderlying layer, and to create a space between the portion of theperitoneum and the underlying layer. The main envelope is returned to acollapsed state. The main envelope is advanced in the direction of thehernia to the boundary of the separated portion of the peritoneum. Themain envelope is re-inflated into an expanded state to separate anadditional portion of the peritoneum from the underlying layer, and toenlarge the space. Finally, insufflation gas is introduced into at leastpart of the space.

In a variation, the collapsing, advancing, and re-inflating steps arerepeated with the main envelope being expanded to a partially expandedstate to create a narrow tunnel between the incision at the umbilicusand the hernia. At the hernia, the main inflatable chamber is inflatedinto a fully expanded state to create a working space that is laterinsufflated.

Before being inserted into a patient, the inflatable envelopes andchambers are deflated and packed into a sheath. A known method ofpacking the chamber in the deflated, compact state is to roll thechamber inwardly from opposing lateral sides as shown in FIG. 18.

Referring to FIG. 34, a problem which occurs when mounting a balloon tothe distal end of delivery device is that the balloon becomes skewed andoff-center when inflated. The balloon becomes skewed and off-centersince the balloon does not have structural support during inflation.

A method of preventing the balloon from becoming skewed and off-centerduring inflation is to attach the balloon away from the distal end sothat a length of the cannula extends into the interior of the balloon asshown in FIG. 35. During inflation, the length of cannula inside theballoon provides structural support and prevents the balloon frombecoming skewed and off-center. A problem which occurs when mounting theballoon away from the distal end of the cannula is that the visual fieldof an endoscope inserted in the device is limited. When dissectingand/or retracting tissue layers, it is preferable to view as much of theballoon.

SUMMARY OF THE INVENTION

The present invention solves the problems associated with known devicesfor separating tissue layers by providing a supporting portion movablebetween an extended position, in which the supporting portion ispositioned within the interior of the inflatable balloon, and aretracted position, in which the supporting portion is positionedoutside the interior of the inflatable balloon. The supporting portionprovides support for the balloon so that the balloon does not becomeskewed and off-center during inflation. A delivery device preferablyincludes an inflation port coupled to a fluid path for inflating theballoon.

The device preferably includes an outer cannula and an inner cannula atleast partially disposed within the outer cannula. The balloon ispreferably mounted to the distal end of the outer cannula. The innercannula preferably defines the supporting portion and is movably coupledto the outer cannula so that the supporting portion is movable betweenthe extended and retracted positions with respect to the balloon.

In a first, preferred device for separating tissue layers, the innercannula is mounted to an insert and the outer tube is mounted to thedelivery device. The insert passes through a port in the delivery deviceand is sildably movable relative to the delivery device. The insertincludes an opening adapted to receive an endoscope. The insert alsopreferably includes a lock for locking the endoscope to the insert. Thefluid path is at least partially defined by an area between the innerand outer cannulas.

In a second, preferred device for separating tissue layers, the innercannula is mounted to the delivery device and the outer cannula isslidably coupled to the inner cannula. First and second stops aremounted to the inner cannula to limiting slidable movement between theextended and retracted positions. A sleeve is mounted to the outercannula. The sleeve has a detent extending inwardly toward the innercannula. The detent is configured to matingly engage the stop to lockthe inner and outer cannulas in the retracted position and extendedpositions, respectively. An elastomeric member is coupled to the sleeve,and forms a substantially fluid tight seal between the sleeve and theinner cannula to maintain fluid pressure in the balloon.

In a third, preferred device for separating tissue layers, the innercannula is mounted to the delivery device and a proximal end of theouter cannula is also mounted to the delivery device. The outer cannulahas a contracting portion which contracts to changing a longitudinallength of the outer cannula. The contracting portion preferably includesa number of longitudinally extending segments. At least a portion of thefluid path is housed within the inner cannula.

In a method of separating tissue layers according to the presentinvention, a balloon is inserted into a patient with a supportingportion extending within the interior of the balloon. The balloon isthen inflated through an inflation port and a fluid path. The supportingportion provides support for the balloon during inflation so that theballoon does not become skewed and off-center. The supporting portion isthen removed from the interior of the balloon so that the field of viewof an endoscope inserted into the interior of the balloon is notlimited.

Other features and advantages of the invention will appear from thefollowing description in which the preferred embodiment has been setforth in detail in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of the abdominal wall showing theperitoneum, the properitoneal fat layer, the properitoneal fascia, andother tissue layers.

FIGS. 2A through 2E show a two-component apparatus according to theinvention, wherein:

FIG. 2A shows the separation component of the two-component apparatusaccording to the invention.

FIG. 2B shows part of the distal part of the separation component of thetwo-component apparatus according to the invention with the mainenvelope in its everted position.

FIG. 2C shows part of the distal part of the separation component of thetwo-component apparatus according to the invention with the mainenvelope in its inverted position.

FIG. 2D shows the insufflation component of the two-component apparatusaccording to the invention with the toroidal inflatable chamber in itscollapsed state.

FIG. 2E shows the insufflation component of the two-component apparatusaccording to the invention with the toroidal inflatable chamber in itsexpanded state.

FIGS. 3A through 3I are longitudinal cross sections of the abdomenillustrating the method according to the invention of using atwo-component apparatus according to the invention to separate theperitoneum from the underlying layer, wherein:

FIG. 3A shows an incision made through the abdominal wall, including theproperitoneal fat layer, excluding the peritoneum.

FIG. 3B shows the distal part of the separation component of atwo-component apparatus according to the invention inserted into theincision. The separation component includes the main envelope in itscollapsed state.

FIG. 3C shows the main envelope inflated to its expanded state toseparate the peritoneum from the underlying layer.

FIG. 3D shows the main envelope returned to its collapsed state.

FIG. 3E shows the separation component removed from the incision.

FIG. 3F shows the distal part of the insufflation component of thetwo-component apparatus according to the invention inserted into theincision.

FIG. 3G shows the toroidal inflatable chamber of the insufflationcomponent inflated to its expanded state and the anchor flange slid intocontact with the skin of the abdominal wall to provide a gas-tight seal.

FIG. 3H shows the working space between the peritoneum and theunderlying layer insufflated with a gas passed through the bore of theinsufflation component.

FIG. 3I shows additional instruments passed through gas-tight trocarsheaths into the insufflated working space to repair the hernia byattaching a mesh patch to the properitoneal fascia.

FIGS. 4A through 4C show the main embodiment of the first one-componentapparatus according to the invention, wherein:

FIG. 4A shows the main embodiment of the first one-component apparatusaccording to the invention with the main envelope in its expanded state.

FIG. 4B shows details of the area marked "A" at the distal end of thetube assembly in FIG. 4A.

FIG. 4C shows the distal part of the tube assembly with the toroidalinflatable chamber in its expanded state.

FIGS. 5A through 5D show the alternative embodiment of the firstone-component apparatus according to the invention, wherein:

FIG. 5A shows the alternative embodiment of the first one-componentapparatus according to the invention with the main envelope in itsexpanded state.

FIG. 5B shows the elongated main envelope of the alternative embodimentof the first one-component apparatus according to the invention.

FIG. 5C shows the distal part of the tube assembly of the alternativeembodiment of the first one-component apparatus according to theinvention with the main envelope in its everted state.

FIG. 5D shows the distal part of the tube assembly of the alternativeembodiment of the first one-component apparatus according to theinvention with the main envelope in its inverted state.

FIGS. 6A through 6H are longitudinal cross sections of the abdomenillustrating the method according to the invention of using a firstone-component apparatus according to the invention to separate theperitoneum from the underlying layer, wherein:

FIG. 6A shows an incision made through the abdominal wall, including theunderlying layer, excluding the peritoneum.

FIG. 6B shows the distal part of the tube assembly of a one-componentapparatus according to the invention inserted into the incision. Thetube assembly includes the main envelope in its collapsed state.

FIG. 6C shows the main envelope inflated to its expanded state toseparate the peritoneum from the underlying layer.

FIG. 6D shows the main envelope returned to its fully collapsed state.

FIG. 6E shows the apparatus advanced into the incision such that theenvelope of the toroidal inflatable chamber clears the incision.

FIG. 6F shows the toroidal inflatable chamber inflated to its expandedstate.

FIG. 6G shows the anchor flange slid into contact with the skin of theabdominal wall. The anchor flange together with the expanded toroidalinflatable chamber provides a gas-tight seal.

FIG. 6H shows the space between the peritoneum and the underlying layerinsufflated with a gas passed through the bore of the apparatus.

FIGS. 7A and 7B show a second embodiment of a one-component apparatusaccording to the invention, wherein:

FIG. 7A shows the second one-component apparatus according to theinvention with the main envelope in its expanded state.

FIG. 7B shows the second one-component apparatus according to theinvention with the main envelope in its collapsed state.

FIG. 8A shows the second one-component apparatus according to theinvention with the main envelope in its expanded state and an endoscopepassed through the bore of the outer tube into the main inflatablechamber.

FIG. 8B shows the second one-component apparatus according to theinvention with the main inflatable chamber in its partially expandedstate and an endoscope passed through the bore of the inner tube andthrough the bore of the main envelope.

FIGS. 9A through 9F are longitudinal cross sections of the abdomenillustrating the method according to the invention of using a secondone-component apparatus according to the invention to separate theperitoneum from the underlying layer, wherein:

FIG. 9A shows an incision made through the abdominal wall, including theunderlying layer, excluding the peritoneum.

FIG. 9B shows the distal part of the tube assembly of a one-componentapparatus according to the invention inserted into the incision. Thetube assembly includes the main envelope in its collapsed state.

FIG. 9C shows the main envelope inflated to its expanded state toseparate the peritoneum from the underlying layer.

FIG. 9D shows the main envelope returned to its partially-collapsedstate.

FIG. 9E shows the anchor flange slid into contact with the skin of theabdominal wall. The anchor flange and the partially-collapsed maininflatable chamber together provide a gas-tight seal.

FIG. 9F shows the space between the peritoneum and the underlying layerinsufflated with a gas passed through the bore of the inner tube of theapparatus.

FIGS. 10A through 10I illustrate the alternative method according to theinvention of using any of the apparatus according to the invention toseparate the peritoneum from the underlying layer near the groin, withthe apparatus inserted through an incision near the umbilicus. FIGS. 10Athrough 10H are longitudinal cross sections of the abdomen, wherein:

FIG. 10A shows an incision made through the abdominal wall, includingthe underlying layer, excluding the peritoneum.

FIG. 10B shows the distal part of the apparatus according to theinvention inserted into the incision. The tube assembly includes themain envelope in its collapsed state.

FIG. 10C shows the main envelope inflated to a partially-expanded stateto separate part of the peritoneum from the underlying layer.

FIG. 10D shows the main envelope returned to its collapsed state.

FIG. 10E shows the apparatus advanced in the direction of the groin tobring the main envelope to the limit of the separated part of theperitoneum.

FIG. 10F shows the main envelope re-inflated to a partially-expandedstate to separate an additional part of the peritoneum from theunderlying layer.

FIG. 10G shows the main envelope advanced to close to the site of thehernia and re-inflated to its fully inflated state to create a workingspace.

FIG. 10H shows the introducer component advanced through the tunnel intothe working space, and the toroidal inflatable chamber inflated to forma gas-tight seal with the entrance of the tunnel.

FIG. 10I is a plan view of the abdomen showing the insufflator componentin position with its distal end in the working space and its toroidalinflatable chamber forming a gas-tight seal with the entrance of thetunnel. The figure also shows the lesser extent to which the peritoneumis detached in the tunnel compared with in the working space.

FIGS. 11A through 11C show a retraction device having a first inflatablechamber for maintaining separation between two tissue layers, wherein:

FIG. 11A shows the first inflatable chamber in a collapsed state andcontained within a perforated sheath.

FIG. 11B and 11C show the first inflatable chamber in an expanded state.

FIGS. 12A and 12B show a second inflatable chamber for maintainingseparation between two tissue layers, wherein:

FIG. 12A is an end view of the second inflatable chamber for maintainingseparation between two tissue layers.

FIG. 12B is a side view of the second inflatable chamber in the expandedstate.

FIGS. 13A through 13C show the construction of the first inflatablechamber, wherein.

FIG. 13A shows the orientation of the first and second sheets, bafflesand release agent before RF welding the baffles and sheets.

FIG. 13B shows an exploded cross-sectional view of FIG. 13A with the RFwelding electrodes in position.

FIG. 13C shows the baffles attached to the first and second sheets.

FIGS. 14A and 14B show a third inflatable chamber for maintainingseparation between two tissue layers, wherein:

FIG. 14A is an end view of the third inflatable chamber.

FIG. 14B is a side view of the third inflatable chamber.

FIGS. 15A and 15B show a fourth inflatable chamber for maintainingseparation between two tissue layers, wherein:

FIG. 15A is an end view of the fourth inflatable chamber.

FIG. 15B is a side view of the fourth inflatable chamber.

FIGS. 16A and 16B show a fifth inflatable chamber for maintainingseparation between tissue layers, wherein:

FIG. 16A is an end view of the fifth inflatable chamber.

FIG. 16B is a side view of the fifth inflatable chamber.

FIGS. 17A and 17B show a retraction device having the fourth inflatablechamber advanced through a tunnel into a working space and an additionalinstrument passing adjacent the fourth inflatable chamber.

FIG. 18 shows a balloon rolled in the known manner with two rolls formedby rolling the balloon inward from opposing outer edges;

FIG. 19 shows deployment of the balloon of FIG. 18 with the top of therolls rubbing against the upper tissue layer;

FIG. 20 shows an isometric view of an inflatable balloon;

FIG. 21 shows a plan view of the inflatable balloon of FIG. 20;

FIG. 22 shows a first portion of the balloon of FIG. 20 displacedinwardly;

FIG. 23 shows a rolling device grasping an end of the first,inwardly-displaced portion between two rods;

FIG. 24 shows the rolling device of FIG. 23 used for rolling-up thefirst inwardly-displaced portion of the balloon;

FIG. 25 shows the rolling device during rolling of the first portion ofthe balloon;

FIG. 26 shows a cross-sectional view of the balloon of FIG. 20 withfirst and second inwardly-displaced portions rolled-up into first andsecond rolls and an obturator positioned therebetween;

FIG. 27 shows the balloon of FIG. 26 during inflation and deploymentbetween tissue layers;

FIGS. 28 and 29 show a cross-sectional view of a balloon packed inaccordance with another preferred method of packing a deflated balloon;

FIGS. 30 and 31 show a cross-sectional view of a balloon packed inaccordance with another preferred method of packing a deflated balloon.

FIG. 32 shows a balloon having accordion-folds;

FIG. 33 shows the balloon of FIG. 32 in a compact state;

FIG. 34 shows a balloon mounted to a distal end of a delivery devicewith the inflated balloon being skewed and off-center;

FIG. 35 shows a balloon mounted away from the distal end of a deliveryand inflation device;

FIG. 36 shows a first balloon cannula system having a delivery device,an insert and obturator;

FIG. 37 is an end view of the delivery device and insert with the inserthaving lips which engage recesses in the delivery device to lock theinsert to the delivery device;

FIG. 38 is an end view of the insert showing the opening adapted toreceive an instrument;

FIG. 39 shows the first balloon cannula system with the balloon in adeflated state;

FIG. 40 shows the first balloon cannula system with an endoscopeinserted through a proximal end of the insert;

FIG. 41 shows the first balloon cannula system with the tubular insertin an extended position so that a supporting portion of an inner cannulaextends into the interior of the balloon during inflation;

FIG. 42 shows the first balloon cannula system with the tubular insertin a retracted position so that the supporting portion of the innercannula is housed within an outer cannula;

FIG. 43 shows a second balloon cannula system having an outer cannulaslidably coupled to an inner cannula;

FIG. 44 shows the second balloon cannula system with a supportingportion of the inner cannula being in a retracted position;

FIG. 45 is a cross-sectional view of a sleeve and a lock ring used tolock the outer cannula to the inner cannula;

FIG. 46 shows a third balloon cannula system with the outer cannulahaving a contracting portion; and

FIG. 47 shows the third balloon cannula system with the inner cannula ina retracted possition.

DETAILED DESCRIPTION OF THE INVENTION

A cross-sectional view of the abdominal wall is shown in FIG. 1. Theabdominal wall includes the various layers of tissue shown. Theperitoneum P is the innermost layer. Underlying the peritoneum areseveral layers of tissue, including the properitoneal fat layer FL andthe properitoneal fascia F. The properitoneal fascia is the layer towhich the mesh patch is preferably attached in hernia repair. Theproperitoneal fat layer separates the peritoneum from the properitonealfascia. The properitoneal fat layer is relatively weak, which enablesthe peritoneum to be separated relatively easily from the fascia.

When the peritoneum is separated from the fascia, separation takes placeat or in the properitoneal fat layer. The properitoneal fat layer canremain attached to the properitoneal fascia, or can come away with theperitoneum. Alternatively, part of the properitoneal fat layer canremain attached to the peritoneum and part of the fat layer can comeaway attached to the peritoneum. Because of the uncertainty in the pointof separation, the layer which is detached will be called theperitoneum, and the layer from which the peritoneum is detached will becalled the underlying layer. Additional layers of tissue lie between theproperitoneal fascia and the skin S.

An inguinal hernia occurs when the contents of the abdominal cavitybreak through the abdominal wall. As described above, a hernia isrepaired by attaching a piece of mesh to the abdominal wall. To preventthe mesh from causing trauma to the bowel, either through irritation ofthe bowel by the rough surface of the mesh, or by adhesion of the bowelto the mesh, it is preferred to attach the mesh to the properitonealfascia. With the mesh attached to the fascia, the peritoneum covers themesh and isolates the bowel from the mesh.

Conventional techniques of attaching the mesh patch to the properitonealfascia, both laparoscopic and normal, involve blunt dissecting theperitoneum away from the properitoneal fascia, working from inside oroutside the belly. The apparatus and methods according to the inventionenable the peritoneum to be separated from the properitoneal fascia andthe mesh patch attached to the fascia without entering the belly.

Although the following description will describe the apparatus andmethods according to the invention with respect to hernia repair, theapparatus and methods are not restricted to hernia repair. The apparatusand methods can equally well be used in other procedures in which onelayer of tissue is separated from another to form a working spacebetween the layers. These procedures include thoracoscopy in patientswith pleural adhesions; pericardioscopy, or the introduction of anendoscope into the pericardial cavity, in patients with pericardialadhesions; retroperitoneal lymph node dissection, in which theperitoneum on the distal aspect of the abdominal cavity is separatedfrom the underlying tissue which includes lymph nodes; and in separatinga blood vessel from surrounding connective tissue in the course of, forexample, a femoropopliteal arterial bypass graft procedure.

1. TWO-COMPONENT APPARATUS AND METHOD OF USING

The two-component form of the apparatus according to the invention isshown in FIGS. 2A through 2C. FIG. 2A shows a partially cut-away view ofthe separation component 1 of the apparatus. In the separationcomponent, the introducer tube 3 is a rigid tube having a bore with acircular cross section that can accommodate an endoscope.

The proximal end of the introducer tube is fitted with a port 5, in theproximal end 7 of which is mounted a flapper valve 2. The shutter 6 ofthe flapper valve is operated by the button 9. The seat 4 of the flappervalve additionally forms a gas-tight seal with an endoscope or otherinstrument inserted though the flapper valve into the bore of theintroducer tube 3. The port 5 is also fitted with a valve 11 to which asupply of a suitable inflation fluid can be connected.

The main envelope 12 defines a main inflatable chamber 13. The mainenvelope is fitted to the distal end 15 of the introducer tube 3. Themain envelope and main inflatable chamber are shown in their collapsedstates. The dotted line 12X indicates the extent of the main envelopewhen the main inflatable chamber 13 in its expanded state. It should benoted that although the main envelope 12 is illustrated as generallyspherical, it can be formed as oblong, "hockey puck" or disc shaped,kidney bean shaped or other shapes as are suited for the particulardissection contemplated.

The main envelope 12 is preferably formed from an elastomeric material,such as latex, silicone rubber, or polyurethane. The main envelope canalso be formed from a thin, inelastic material such as Mylar®,polyethylene, nylon, etc. If an inelastic material is used, it should besuitably packaged to fit inside the bore of the introducer tube 3 whenin its collapsed state.

The preferred elastomeric main envelope 12 can be simply attached to thedistal end 15 of the introducer tube 3 by stretching the main envelopeover the distal end of the introducer tube, as shown in FIG. 2B. Themain envelope is then kept in place by friction resulting from thetension caused by stretching. A suitable adhesive, such as an epoxy orcyanoacrylate adhesive, may additionally or alternatively be used. Othermeans of attaching the main envelope to the inside or the outside of theintroducer tube can be used.

After attachment, the main envelope 12 is inverted into the bore of theintroducer tube, as shown in FIG. 2C. Inverting the main envelope intothe bore of the introducer tube makes it easier to use the introducertube to pass the main envelope through an incision and place it adjacentto the peritoneum, as will be described next.

The first part of a method according to the invention of using theseparation component 1 of a two-component apparatus according to theinvention to separate a first layer of tissue from a second layer oftissue will next be described. As an illustration, separating theperitoneum from the properitoneal fascia in the course of repairing ahernia will be described.

FIGS. 3A through 3H show a longitudinal cross section of the lowerabdomen. An incision about 12-15 mm. long is made in the abdominal wallAW, and is carried through the abdominal wall as far as, and including,the properitoneal fat layer FL. The distal end 15 of the introducer tube3 of the separation component 1 is then inserted into the incision tobring the distal end into contact with the peritoneum P. Additionalgentle pressure detaches the part of the peritoneum in the immediatevicinity of the incision from the underlying layer, as shown in FIG. 3B.FIG. 3B shows the peritoneum detached from the properitoneal fat layerFL. The main envelope cannot be seen in these figures because it isinverted within the bore of the introducer tube 3.

A source of a suitable inflation fluid (not shown) is connected to thevalve 11. A gas, preferably air, is the preferred inflation fluid, butother gases, such as carbon dioxide, can be used. A liquid, such assaline solution, can be used, but liquids are less preferable to gasesbecause they change the optical properties of any endoscope insertedinto the main inflatable chamber 13. The flow of inflation fluid isturned on, which ejects the main envelope 12 of the main inflatablechamber 13 from the bore of the introducer tube 3.

The inflation fluid progressively expands the main envelope 12, andhence the main inflatable chamber 13 defined by the main envelope, intoan expanded state. The main envelope expands between the peritoneum andthe properitoneal fascia, and gently and progressively detaches anincreasing area of the peritoneum from the underlying layer as itexpands. When the main envelope is in its expanded state, the maininflatable chamber is preferably about 4"-6" (100-150 mm) in diameter.

Early in the process of expanding the main envelope 12, an endoscope Eis inserted into the flapper valve 2 in the port 5, as shown in FIG. 3C.The endoscope E is passed through the bore of the introducer tube 3 intothe main inflatable chamber 13. Once partially expanded, the mainenvelope 12 is sufficiently transparent for the extent of the detachmentof the peritoneum to be observed through the endoscope.

When a sufficient area of the peritoneum has been detached, the supplyof inflation fluid is turned off. The inflation fluid is then ventedfrom the main inflatable chamber, and the main envelope 12 progressivelyreturns to its collapsed state. The peritoneum remains detached from theproperitoneal fascia, however, as shown in FIG. 3D. The separationcomponent 1, including the collapsed main envelope, is then withdrawnfrom the incision I (FIG. 3E).

The insufflation component 21 of the two-component apparatus, shown inFIG. 2D, will next be described. The insufflation component 21 comprisesan inner tube 35 and an outer tube 37 mounted coaxially, with the outertube covering the inner tube over most of the length of the inner tube.The inner tube is similar to the introducer tube 3 (FIG. 2A), and is arigid tube having a bore with a circular cross section that canaccommodate a 10 mm endoscope.

The proximal end of the inner tube 35 is fitted with a port 25, theproximal end 27 of which has a flapper valve 32. The shutter 36 of theflapper valve is operated by the button 29. Additionally, the seat 34 ofthe flapper valve forms a gas-tight seal with an endoscope (not shown)or an obturator, such as the obturator 33, inserted though the flappervalve into the bore of the inner tube 35. The port 25 is also fittedwith a first valve 31 to which a supply of a suitable insufflation fluidcan be connected.

The distal end 41 of the outer tube 37 stops short of the distal end 39of the inner tube 35. The insufflation component 21 includes a toroidalinflatable chamber 43. The envelope 45 of the toroidal inflatablechamber is a cylindrical piece of a thin elastomeric material, such aslatex, silicone rubber, or polyurethane. The envelope 45 is placed overthe distal ends of the inner tube and the outer tube. The proximal end47 of the envelope is attached to the distal end 41 of the outer tube,and the distal end 49 of the envelope is attached to the distal end 39of the inner tube 35.

The bore of the outer tube 37 is spaced from the outer surface of theinner tube 35. The annular space 51 between the inner tube and the outertube inter connects the toroidal inflatable chamber 43 and a secondvalve 53. The second valve 53 is connected to a source of a suitableinflation fluid (not shown). Thus, the toroidal inflatable chamber 45can be inflated using an inflation fluid passing into the toroidalinflatable chamber via the second valve 53 and the annular space 51. Thetoroidal inflatable chamber is shown in its collapsed state in FIG. 2D,and in its expanded state in FIG. 2E.

The anchor flange 55 is slidably mounted on the outer tube 37, and canbe locked in a desired position along the length of the outer tube witha simple over-center action locking lever (not shown). As will bedescribed in detail below, the anchor flange and the toroidal inflatablechamber, in its expanded condition, enable the insufflator component 21to form a gas-tight seal to prevent insufflation gas passed through theinsufflator component from escaping.

The use of the insufflation component 21 in the second part of themethod according to the invention of using the two-component apparatusaccording to the invention will next be described. It is preferred touse the insufflation component 21 in conjunction with the first part ofthe method and the separation component I for dissecting the first andsecond tissue layers, however, the second part of the method and theinsufflation component 21 may be used in conjunction with any otherdissection method or apparatus including manual dissection with anendoscope, graspers, operating scope or any blunt instrument which maybe used to dissect the tissue layers by sweeping the area between thelayers.

An obturator 33, having a blunt tip 59, is preferably inserted throughthe flapper valve 32 in the port 25 into the bore of the inner tube 35.The tip of the obturator projects beyond the distal end of the innertube to provide the insufflation component 21 with a blunt nose. Theblunt nose enables the distal end of the insufflation component to beatraumatically inserted into the properitoneal space through theincision I. The insufflation component is advanced through the incisionuntil the proximal end of the cylindrical envelope 45 is in theproperitoneal space, clear of the incision, as shown in FIG. 3F.

A suitable source (not shown) of an inflation fluid is attached to thesecond valve 53. A gas, such as air or carbon dioxide, can be used forthe inflation fluid; alternatively, a liquid, such as saline can beused. Since the volume of inflation fluid required to inflate thetoroidal inflatable chamber is small, about 15 ml in the preferredembodiment, the inflation fluid can be forced into the toroidalinflatable chamber from a large syringe. Inflation fluid is fed into thetoroidal inflatable chamber 43 to expand the toroidal inflatable chamberto its expanded condition, as shown in FIG. 3G.

The anchor flange 55 is then advanced in the direction of the arrow 59along the outer tube 37 to bring the anchor flange into contact with theskin S of the abdominal wall AW. The insufflation component 21 is thengripped, and the anchor flange is further advanced slightly. This forcesthe expanded toroidal inflatable chamber 43 into contact with theunderlying layer, and slightly compresses the abdominal wall, includingthe underlying layer, but excluding the peritoneum P, between thetoroidal inflatable chamber and the anchor flange. Once adjusted, theanchor flange is locked in position on the outer tube. The expandedtoroidal inflatable chamber is held against the underlying layer, andforms a gas-tight seal between the insufflation component and theabdominal wall, including the underlying layer, excluding theperitoneum.

A suitable source (not shown) of an insufflation gas is attached to thefirst valve 31, and insufflation gas is passed through the bore of theinner tube 35 into the working WS space between the peritoneum P and theunderlying layer created by separating by the peritoneum from theunderlying layer using the separation component of the apparatus in thefirst part of the method described above. The pressure of theinsufflation gas re-separates the peritoneum from the underlying layer,as shown in FIG. 3H, and provides a working space in which repair of thehernia can be carried out. The obturator is removed from the bore of theinner tube 35. The bore of the inner tube 35 can then be used to passinstruments, such as the endoscope E, into the working space to performthe repair procedure. Insufflation pressure is maintained by the flappervalve 32.

As part of the hernia repair procedure, additional gas-tight trocarsheaths are inserted through the abdominal wall into the working spaceWS, shown in FIG. 3I. An endoscope (not shown) can be passed into theworking space through the bore of the inner tube 35, or through one ofthe additional trocar sleeves for observation. If the properitoneal fatlayer FL remains attached to the properitoneal fascia F, it is scrapedoff the fascia around the site of the hernia so that the patch can beattached directly to the fascia.

A patch M, preferably a Dacron® or Teflon® mesh, is shown gripped by thegrippers G, and passed through the trocar sleeve TS2 into the workingspace. Using the grippers, the patch is manipulated to place it incontact with the properitoneal fascia F over the site of the hernia. Thepatch is attached to the properitoneal fascia by staples inserted usingthe stapler ST passed through the trocar sleeve TS1 into the workingspace. Sutures can alternatively be used to attach the patch to theproperitoneal fascia.

After the treatment procedure is completed, the first valve 31 isoperated to release the insufflation gas from the working space. Thesecond valve 53 is operated to release the inflation fluid from thetoroidal inflatable chamber 43. The envelope 45 of the toroidalinflatable chamber returns to its collapsed state, flush with the outersurfaces of the inner tube and the outer tube. The insufflatingcomponent is then withdrawn from the incision, and the incision isclosed using sutures or clips. The pressure of the viscera against theperitoneum returns the peritoneum into contact with the underlyinglayer. Over time, the peritoneum reattaches to the underlying layer.

2. FIRST ONE-COMPONENT APPARATUS

(a) Main Embodiment

The separation component can be dispensed with, and the insufflationcomponent can be modified to provide the first embodiment of a onecomponent apparatus according to the invention. The first one-componentapparatus is shown in FIG. 4A. The first one-component apparatus 121 issimilar to the insufflation component just described. Like componentswill use the same reference numbers with 100 added. The first onecomponent apparatus comprises a tube assembly 160, including an innertube 135 coaxially mounted inside an outer tube 137. The outer tubecovers the inner tube over most of the length of the inner tube. Theinner tube is a rigid tube having a bore with a circular cross sectionthat can accommodate an endoscope (not shown).

The proximal end of the inner tube 135 is fitted with a port 125, theproximal end 127 of which includes a flapper valve 132. The shutter 136of the flapper valve is operated by the button 129. Additionally, theseat 134 of the flapper valve forms a gas-tight seal with an endoscope(not shown), or other instrument, inserted though the flapper valve intothe bore of the inner tube 135. The port 125 is also fitted with a firstvalve 131 to which a supply of a suitable insufflation fluid can beconnected.

Unlike the insufflator component of the two-component apparatus, thedistal end 141 of the outer tube 137 extends as far as the distal end139 of the inner tube 135. The tubes are connected together over adistal portion 167 of their lengths (see detail in FIG. 4B). Acircumferential groove 169 is formed in the inner wall of the distalportion 167. A groove with a wedge-shaped cross section is shown. Thecircumferential groove can have other cross sections, such as square, orsemi-circular. The circumferential groove retains the main envelope 112,which defines the main inflatable chamber 113, in the bore of the innertube, as will be described in more detail below.

The envelope 145 of the toroidal inflatable chamber 143 covers thedistal part of the tube assembly 160. The envelope 145 is a cylindricalpiece of a thin elastomeric material, such a latex, silicone rubber, orpolyurethane. The proximal end 147 and the distal end 149 of theenvelope are attached to the outer surface 163 of the tube assemblyusing a circumferential line of adhesive applied at each end of theenvelope. An epoxy or cyanoacrylate adhesive is preferably used. Whenthe toroidal inflatable chamber is in its collapsed state, the envelope145 lies almost flush with the outer surface of the tube assembly 160.

The outer tube 137 is spaced from the inner tube 135 over at least partof its circumference. The space 151 between the inner tube and the outertube, and a radial passage 161 through the wall of the outer tubeinterconnect the toroidal inflatable chamber 143 and the second valve153. The second valve 153 is connected to a source of a suitableinflation fluid (not shown). The toroidal inflatable chamber is shown inits collapsed state in FIGS. 4A and 4B, and in its expanded state inFIG. 4C.

The anchor flange 155 is slidably mounted on the tube assembly 160, andcan be locked in a desired position along the length of the tubeassembly with a simple over-center action locking lever (not shown). Aswill be described in detail below, the anchor flange and the toroidalinflatable chamber, in its expanded condition, form a gas-tight seal toprevent insufflation gas from escaping.

The first one-component apparatus also includes a main envelope 112detachably attached to the bore of the inner tube 135. The main envelopedefines the main inflatable chamber 113. The main envelope is preferablyformed of an elastomeric material such as latex, silicone rubber, orpolyurethane. The main envelope can also be formed from a thin,inelastic material such as Mylar®, polyethylene, nylon, etc. If aninelastic material is used, it should be suitably packaged to fit insidethe bore of the inner tube when in its collapsed state.

The main envelope 112 is formed such that it has a substantiallyspherical shape when it is in its expanded state, and is also formedwith a neck 165. The neck has an outside diameter substantially equal tothe diameter of the bore of the inner tube 135. The neck 165 can berolled outwards a number of times, as in the neck of a common toyballoon, or the neck can be attached to a suitable O-ring 171, as shownin FIG. 4B. The rolled neck, or the O-ring attached to the neck, engageswith the circumferential groove 169 in the inner wall in the inner tubeto attach the main envelope 112 to the inner tube. The main envelope ishoused in the bore of the inner tube when the main inflatable chamber isin its collapsed state.

The rip cord 173 is attached to the neck 165 of the main envelope 112,runs proximally up the bore of the inner tube 135, and emerges from theport 125 through the flapper valve 132. The part of the rip cord 173emerging from the flapper valve can be gripped and pulled in a proximaldirection to release the rolled neck 165 or the O-ring 171 from thecircumferential groove 169. By pulling further on the rip cord, theentire main envelope can be pulled proximally through the bore of theinner tube.

(b) Alternative Embodiment

An alternative embodiment of the first one-component apparatus having anelongated main envelope 112A is shown in FIG. 5A. The tube assembly 160Aincludes the inner tube 135A mounted coaxially inside the outer tube137A, with the proximal and distal ends of the tubes interconnected. Thespace 151A between the inner tube and the outer tube communicates withthe toroidal inflatable chamber through the radial passage 161A in thewall of the outer tube. The space between the inner tube and the outertube also communicates with the toroidal chamber inflation valve 153A.

The bore of the inner tube 135A communicates with the port 125A, fittedwith the insufflation valve 185. The port 125A is also fitted with aflapper valve 132A, including the flapper valve seat 134A, whichmaintains gas pressure when the apparatus is used for insufflation. Theflapper valve seat 134A also provides a gas-tight seal around anyinstrument, such as the endoscope E, passed through the flapper valve.

The elongated main envelope 112A is shown in FIG. 5B. The main envelopeis an elongated cylinder with a closed distal end 177. The main envelopeis preferably formed from an elastomeric material, such as latex,silicon rubber, or polyurethane. Attached to the proximal end of themain envelope is a manifold 175 which mates with the proximal face 127Aof the port 125A. The manifold 175 is fitted with an O-ring seal 187,which forms a gas-tight seal with any instrument passed through it. Themanifold 175 is also fitted with the main chamber inflation valve 131Ato which a supply (not shown) of a suitable inflation fluid can beattached to inflate the main inflatable chamber 112A.

The elongated main envelope 112A is passed through the flapper valve132A into the bore of the inner tube 135A. The manifold 175 is engagedwith the proximal face 127A of the port 125A. When the manifold isengaged, the distal end 177 of the main envelope projects beyond thedistal end of the tube assembly 160A, as shown in FIG. 5C. The distalend of the main envelope is then inverted int 135A, as shown in FIG. 5D.

An endoscope, or some other suitable instrument, is inserted through theO-ring seal 187 to seal the manifold before inflation fluid is passedthrough the main chamber inflation valve 131A to inflate the maininflatable chamber 113A.

Alternatively, the seal 187 can be replaced by an additional flappervalve (not shown) so that the main inflatable chamber can be inflatedwithout the need to use an instrument to seal the manifold.

When inflation fluid is passed into the main inflatable chamber 113Athrough the valve 131A, the distal end 177 of the main envelope 112A isejected from the inner tube 135A. The inflation fluid then progressivelyexpands the main envelope 112A, and hence the main inflatable chamber113A defined by the main envelope, into an expanded state, as shown inFIG. 5A. The part of the main envelope inside the inner tube is subjectto the same inflation pressure as the distal end 177 of the mainenvelope, but is constrained by the inner tube and so does not inflate.

After using the main envelope 112A to separate the peritoneum away fromthe underlying layer, as will be described in detail below, theinflation pressure fluid is vented from the main inflatable chamber113A, and the main envelope returns to its collapsed state. When themain envelope is in its collapsed state, it can move freely in the boreof the inner tube 135. The main envelope is removed from the inner tubeby disengaging the manifold 175 from the proximal face 127A of the port125A, and using the manifold 175 to pull the main envelope proximallythrough the bore of the inner tube.

Inflation fluid for the toroidal inflatable chamber the envelope ofwhich 145A is shown in FIG. 5A, is passed through the toroidal chamberinflation valve 153A. Insufflation gas is passed through theinsufflation valve 185.

The toroidal inflatable chamber and the anchor flange 155A of thealternative embodiment of the first one-component apparatus are the sameas in the main embodiment, and will therefore not be described.

(c) Method of Using the First One-Component Apparatus (Both Forms)

The method according to the invention of using either form of the firstone-component apparatus according to the invention to separate a firstlayer of tissue from a second layer of tissue will next be described. Asan illustration, separating the peritoneum from the properitoneal fasciain the course of repairing a hernia will be described.

FIGS. 6A through 6H show a longitudinal cross section of the lowerabdomen. An incision about 12-15 mm. long is made in the abdominal wallAW, and carried through the abdominal wall as far as, and including theproperitoneal fat layer FL, as shown in FIG. 6A. The distal end 115 ofthe tube assembly 160 of the one-component apparatus 121 is theninserted into the incision to bring the distal end into contact with theperitoneum. Additional gentle pressure detaches the part of theperitoneum in the immediate vicinity of the incision from the underlyinglayer, as shown in FIG. 6B. FIG. 6B shows the peritoneum detached fromthe properitoneal fat layer FL. The main envelope cannot be seen inthese figures because it is inverted within the bore of the tubeassembly.

A source of inflation fluid (not shown) is connected to the valve 131. Agas, preferably air, is the preferred inflation fluid, but other gases,such a carbon dioxide can be used. A liquid, such as saline solution canbe used, but liquids are less preferable to gases because they changethe optical properties of any endoscope inserted into the maininflatable chamber 113. The flow of inflation fluid is turned on, whichejects the main envelope 112 from the bore of the tube assembly 160.

The inflation fluid progressively expands the main envelope 112, andhence the main inflatable chamber 113 defined by the main envelope, intoan expanded state. The main envelope expands between the peritoneum Pand the properitoneal fat layer FL, and gently and progressivelydetaches an increasing area of the peritoneum from the underlying layeras it expands. When the main envelope is in its expanded state, the maininflatable chamber is preferably about 4"-6" (100-150 mm) in diameter.

Early in the process of expanding the main envelope 112, an endoscope Eis inserted into the flapper valve 132 in the port 125, as shown in FIG.6C. The endoscope E is passed through the bore of the tube assembly 160into the main inflatable chamber 113. Once the main envelope ispartially expanded, the main envelope is sufficiently transparent forthe extent of the detachment of the peritoneum to be observed using theendoscope.

When a sufficient area of the peritoneum is detached, the supply ofinflation fluid is turned off. The inflation fluid is then vented fromthe main inflatable chamber 113, and the main envelope progressivelyreturns to its collapsed state. The peritoneum remains detached from theunderlying layer, however, as shown in FIG. 6D. The main envelope isthen removed from the bore of the tube assembly 160. The differentmethods of removing the main envelope from the bore of the tube assemblyfor the two different forms of the first one-component apparatus aredescribed above.

After the main envelope 112 has been removed from the bore of the tubeassembly, the tube assembly is advanced into the incision in thedirection of the arrow 162 until the proximal end of the envelope 145 ofthe toroidal inflatable chamber is in the properitoneal space, clear ofthe incision, as shown in FIG. 6E.

A suitable source (not shown) of an inflation fluid is attached to thevalve 153. A gas, such as air or carbon dioxide, can be used for theinflation fluid; alternatively, a liquid, such as saline can be used.Since the volume of inflation fluid required to inflate the toroidalinflatable chamber is small, about 15 ml in the preferred embodiment,the inflation fluid can be contained in a large syringe. Inflation fluidis fed into the toroidal inflatable chamber 43 to expand the toroidalinflatable chamber to its expanded condition, as shown in FIG. 6F.

The anchor flange 155 is then advanced in the direction of the arrow 159along the tube assembly 160 to bring the anchor flange into contact withthe skin S of the abdominal wall AW. The tube assembly 160 is thengripped, and the anchor flange is further advanced slightly. This forcesthe expanded toroidal inflatable chamber 143 into contact with theunderlying layer, and slightly compresses the abdominal wall AW,including the underlying layer but excluding the peritoneum P, betweenthe expanded toroidal inflatable chamber and the anchor flange, as shownin FIG. 6G. Once adjusted, the anchor flange is locked in position onthe tube assembly. The expanded toroidal inflatable chamber is heldagainst the underlying layer and forms a gas-tight seal with theabdominal wall, excluding the peritoneum.

A suitable source (not shown) of an insufflation gas is attached to thefirst valve 131, and insufflation gas is passed through the bore of theinner tube 135 into the working space WS between the peritoneum P andthe underlying layer created by separating the peritoneum from theunderlying layer. The pressure of the insufflation gas re-separates theperitoneum from the underlying layer, as shown in FIG. 6H, and providesa working space in which repair of the hernia can be carried out. Thebore of the tube assembly 160 can be used to pass instruments, such asthe endoscope E, into the working space to perform the repair procedure.When no instrument is inserted into the bore of the tube assembly,insufflation pressure is maintained by the flapper valve.

As part of the hernia repair procedure, additional gas-tight trocarsleeves (not shown) are inserted through the abdominal wall into theworking space. The same procedure as described above in connection withFIG. 31 is used to attach a mesh patch to the properitoneal fascia overthe site of the hernia. The process can be observed with the aid of anendoscope (not shown) passed through the bore of the tube assembly 160,or through one of the additional trocar sleeves.

After the treatment procedure is completed, the valve 131 is operated torelease the insufflation gas from the working space WS. The valve 153 isoperated to release the inflation fluid from the toroidal inflatablechamber 143, which releases compression of the abdominal wall AW,excluding the peritoneum. The toroidal inflatable chamber returns to itscollapsed state, with its envelope 145 flush with the outer surface thetube assembly 160. The tube assembly is then withdrawn from theincision, and the incision is closed using sutures or clips. Thepressure of the viscera against the peritoneum returns the peritoneuminto contact with the underlying layer. Over time, the peritoneumreattaches to the underlying layer.

3. SECOND ONE-COMPONENT APPARATUS

(a) Second One-Component Apparatus

A second embodiment of a one-component apparatus is shown in FIGS. 7Aand 7B. The second one-component apparatus 121 is similar to the firstone-component apparatus just described. However, the secondone-component apparatus has a substantially spherical toroidal maininflatable chamber, that avoids the need to detach and remove the mainenvelope at the end of the separation process. Also, in the secondone-component apparatus, a single toroidal main inflatable chamberprovides the separating function of the main inflatable chamber and thesealing function of the toroidal inflatable chamber of the firstone-component apparatus.

In the following description, similar components will use the samereference numbers with an additional 100 added.

The second one-component apparatus comprises a tube assembly 260,including an outer tube 237 to which is attached a twin port assembly224 is attached. The port assembly includes a first port 226 and asecond port 228. The first port is provided with a first flapper valve202, including the flapper valve seat 204. The second port is providedwith a second flapper valve 206, including the flapper valve seat 208.Each flapper valve seat additionally forms a gas-tight seal with aninstrument passed through it.

The tube assembly 260 also includes the inner tube 235. The inner tubehas a length that is shorter than the length of the outer tube 237. Theproximal end 210 of the inner tube is flexibly attached to the proximalend 222 of the outer tube 237 and to the first port 226. The flexibleattachment enables the distal end 214 of the inner tube to move in thedirection shown by the arrow 216. The first port communicates with thebore of the inner tube 235, and the second port communicates with thebore of the outer tube 237.

The insufflation valve 285 communicates with the first port 226, and thebore of the inner tube 235. The main chamber inflation valve 231communicates with the second port 228, and the bore of the outer tube237.

The main envelope 212 defines the main inflatable chamber 213 andcomprises a cylindrical piece of an elastomeric material such a latex,silicone rubber, or polyurethane. The apparatus is shown with its mainenvelope in its collapsed state in FIG. 7B, in which the structure ofthe main envelope can also be seen. The main envelope preferably has adiameter smaller than the outside diameter of the inner tube. One end230 of the main envelope is attached to the distal end 214 of the innertube 235 by means of a suitable adhesive, such as an epoxy orcyanoacrylate adhesive. The other end 232 of the main envelope iseverted (i.e., turned back on itself to bring the inside surface 234 ofthe main envelope to the outside) and attached to the distal end 236 ofthe outer tube using the same type of adhesive. The main envelope ispreferably attached to the outer surfaces of the inner tube and theouter tube.

The apparatus is shown with the main envelope 212 in its expanded statein FIG. 7A. A suitable source of inflation gas is connected to the valve231 and flows into the main inflatable chamber through the bore of theouter tube 237. The pressure acting on the surface 238 of the mainenvelope 212 causes the main envelope to assume the toroidal shape shownin FIG. 7A to define the toroidal main chamber 213. FIGS. 7A and 7B showthe correspondence between the surfaces 234 and 238 of the main envelopewhen the main envelope is in its collapsed state (FIG. 7B) and in itsexpanded state (FIG. 7A).

The anchor flange 255 is slidably mounted on the tube assembly 260, andcan be locked in a desired position along the length of the tubeassembly. The anchor flange 255 is similar to the anchor flange 55 (FIG.2A) and so will not be described further.

In FIG. 8A, an endoscope E is shown passed through the second flappervalve 206, the second port 228, and the bore of the outer tube 237 intothe main inflatable chamber 213. The flexible mounting of the inner tube235 in the outer tube enables the endoscope to displace the inner tube235 in direction of the arrow 216 to gain access to the main inflatablechamber. The endoscope is inserted through the second port into the maininflatable chamber during the separation phase of using the apparatus toobserve the extent of the separation of tissue.

In FIG. 8B, an endoscope E is shown passed through the first flappervalve 202, the first port 226, the bore of the inner tube 235, and thebore 234 of the main envelope 212. The distal part of the endoscopeemerges from the bore of the main envelope, and can be advanced beyondthe main inflatable chamber 213 to observe the site of the hernia moreclosely. The endoscope is inserted through the first port, the innertube, and the bore of the main envelope during the insufflation phase ofusing the apparatus. Instruments other than endoscopes can also bepassed to the site of the hernia through the first flapper valve, thefirst port, the inner tube, and the bore of the main envelope ifdesired.

Also in FIG. 8B, the main envelope 212 is shown in the partiallycollapsed state that it preferably assumes during the insufflation phaseof the procedure. In this part of the procedure, the partially collapsedmain inflatable chamber and the anchor flange 255 together provide agas-tight seal to prevent the leakage of insufflation gas.Alternatively, this part of the procedure can be carried out with themain inflatable chamber in a fully expanded state.

(b) Method of Using the Second One-Component Apparatus

The method according to the invention of using the second embodiment ofthe one-component apparatus according to the invention to separate afirst layer of tissue from a second layer of tissue will next bedescribed. As an illustration, separating the peritoneum from theproperitoneal fascia in the course of repairing a hernia will bedescribed.

FIGS. 9A through 9F show a longitudinal cross section of the lowerabdomen. An incision about 12-15 mm long is made in the abdominal wallAW, and carried through the abdominal wall as far as, and including, theproperitoneal fat layer FL, as shown in FIG. 9A. The distal end 215 ofthe tube assembly 260 of the second one-component apparatus 221 is theninserted into the incision to bring the distal end into contact with theperitoneum P. Additional gentle pressure detaches the part of theperitoneum in the immediate vicinity of the incision from the underlyinglayer, as shown in FIG. 9B. FIG. 9B shows the peritoneum detached fromthe properitoneal fat layer FL. The main envelope cannot be seen inthese figures because it is inverted within t he bore of the tubeassembly.

A source of inflation fluid (not shown) is connected to the valve 231. Agas, preferably air, is the preferred inflation fluid, but other gases,such a carbon dioxide can be used. A liquid, such as saline solution canbe used, but liquids are less preferable to gases because they changethe optical properties of any endoscope inserted into the maininflatable chamber. The flow of inflation fluid is turned on, whichejects the main envelope 212 from the bore of the tube assembly 260.

The inflation fluid progressively expands the main envelope 212, andhence the main inflatable chamber 213 defined by the main envelope, intoa n expanded state. The main envelope expands between the peritoneum Pand the properitoneal fat layer FL, and gently and progressivelyseparates an increasing area of the peritoneum from the underlying layeras it expands. When the main envelope is in its expanded state, the maininflatable chamber is preferably about 4"-6" (100-150 mm) in diameter.

Early in the process of expanding the main envelope 212, an endoscope Eis inserted into the first flapper valve 202, as shown in FIG. 9C. Theendoscope E is passed through the bore of the outer tube 237 into themain inflatable chamber 213. Once partially expanded, the main envelope212 is sufficiently transparent for the extent of the separation of theperitoneum to be observed using the endoscope.

When a sufficient area of the peritoneum is separated, the supply ofinflation fluid is turned off. The endoscope E is removed from the maininflatable chamber 213. The valve 231 is then opened to allow inflationfluid to vent partially from the main inflatable chamber 213. The mainenvelope 212 progressively returns part-way towards its collapsed state,as shown in FIG. 9D. Alternatively, the main envelope may be kept fullyexpanded.

The anchor flange 255 is then advanced in the direction of the arrow 259along the tube assembly 260 to bring the anchor flange into contact withthe skin S of the abdominal wall AW. The tube assembly 260 is thengripped, and the anchor flange is further advanced slightly. This forcesthe main inflatable chamber 213 into contact with the underlying layer,and slightly compresses the abdominal wall, including the underlyinglayer but excluding the peritoneum, between the main inflatable chamberand the anchor flange, as shown in FIG. 9E. Once adjusted, the anchorflange is locked in position on the tube assembly. The main inflatablechamber is held against the underlying layer and forms a gas-tight sealwith the abdominal wall, excluding the peritoneum.

A suitable source (not shown) of insufflation gas is attached to thesecond valve 285, and insufflation gas is passed through the bore of theinner tube 235, and the bore 234 of the main envelope, into the workingspace WS between the peritoneum P and the underlying layer. The pressureof the insufflation gas re-separates the peritoneum from the underlyinglayer, as shown in FIG. 9F, and provides a working space in which repairof the hernia can be carried out.

Instruments, such as the endoscope E, can be passed through the secondflapper valve 206, the bore of the inner tube 235, and the bore 234 ofthe main envelope, as shown in FIG. 8B, into the working space toperform the repair procedure. When no instrument is inserted into thebore of the inner tube, insufflation pressure is maintained by thesecond flapper valve.

As part of the hernia repair procedure, additional gas-tight trocarsleeves (not shown) are inserted through the abdominal wall into theworking space. The same procedure as described above in connection withFIG. 3I is used to attach a mesh patch to the properitoneal fascia overthe site of the hernia. The process can be observed with the aid of anendoscope (not shown) passed into the working space through the bore ofthe inner tube 235, or through one of the additional trocar sleeves.

After the treatment procedure is completed, the valve 285 is operated torelease the insufflation gas from the working space. The valve 231 isoperated to release the inflation fluid from the main inflatable chamber213, which releases compression from the abdominal wall, excluding theperitoneum. The main envelope returns to its collapsed state inside thebore of the outer tube 237.

The tube assembly is then withdrawn from the incision, and the incisionis closed using sutures or clips. The pressure of the viscera againstthe peritoneum returns the peritoneum into contact with the underlyinglayer. Over time, the peritoneum reattaches to the underlying layer.

4. HERNIA REPAIR METHOD WITH INCISION AT THE UMBILICUS

The hernia repair methods described so far show the incision placedclose to the site of the hernia. In practice, it is preferred to makethe incision at or near the umbilicus because the boundary between theperitoneum and the properitoneal fat layer can be more directly accessednear the umbilicus. The midline location of the umbilicus is devoid ofmuscle layers that would otherwise need to be traversed to reach theproperitoneal fat layer.

Apparatus of the types described above inserted through an incision atthe umbilicus would require a very large main inflatable chamber todetach the peritoneum from the umbilicus to the groin. Instead, in themethod according to the invention to be described next, an apparatus ofany one of the types described above is used to provide a tunnel from anincision at the umbilicus to the site of the hernia in the groin, andthen to provide an insufflated working space at the site of the hernia.

The main envelope is partially expanded, collapsed, and advanced towardsthe site of the hernia. This sequence is repeated to progressivelyseparate the peritoneum from the underlying layer and form the tunnelfrom the umbilicus to the site of the hernia. Then, at or near the siteof the hernia, the main envelope is fully expanded to provide theworking space at the site of the hernia. The working space is theninsufflated to maintain the separation of the peritoneum from theunderlying layer.

The following method can be practiced using the two-component embodimentof the apparatus, or any of the one-component embodiments of theapparatus. The method will be described using the two-componentapparatus.

An incision about 12-15 mm long is made in the abdominal wall AW, and iscarried through the abdominal wall as far as, and including, theproperitoneal fat layer FL. The incision is made at the umbilicus U, asshown in FIG. 10A.

The distal end 15 of the introducer tube 3 of the separation component 1is then inserted into the incision to bring the distal end into contactwith the peritoneum P. Additional gentle pressure detaches the part ofthe peritoneum in the immediate vicinity of the incision from theunderlying layer, as shown in FIG. 10B. In FIG. 10B, the peritoneum isshown detached from the properitoneal fat layer FL. The main envelopecannot be seen in these figures because it is inverted within the boreof the introducer tube 3.

A source of a suitable inflation fluid (not shown), as previouslydescribed, is connected to the valve 11. The flow of inflation fluid isturned on, which ejects the main envelope 12 of the main inflatablechamber 13 from the bore of the introducer tube 3. The inflation fluidprogressively expands the main envelope 12, and hence the maininflatable chamber 13 defined by the main envelope, into apartially-expanded state, as shown in FIG. 10C. The main envelopeexpands between the peritoneum and the properitoneal fat layer FL, andgently and progressively detaches an increasing area of the peritoneum Pfrom the underlying layer near the umbilicus as it expands.

An endoscope (not shown) can be inserted into the main inflatablechamber 13 through the flapper valve 2 and the bore of the introducertube 3. The endoscope can be used to observe the extent of theseparation of the peritoneum, as described above.

When the main envelope 12 expanded such that the main inflatable chamber13 is about one-fourth of its fully-expanded diameter, i.e., about1.0"-1.5" (25-37 mm) in diameter, the supply of inflation fluid isturned off. The valve 11 is then operated to vent inflation fluid fromthe main inflatable chamber 13. The main envelope progressively returnsto its collapsed state, as shown in FIG. 10D. The peritoneum DP that wasseparated by the main inflatable chamber remains detached from theunderlying layer, however, as shown. Alternatively, the main envelopecan be inflated to a fully-expanded state.

The separation component 1, including the collapsed main envelope 12, isthen manipulated in the direction indicated by the arrow 14, and then inthe direction indicated by the arrow 16, to advance the distal part 15of the introducer tube 3 to the limit of the detached part of theperitoneum DP in the direction of the groin, as shown in FIG. 10E. Anendoscope E inserted through the flapper valve 2 into the bore of theintroducer tube 3 enables the position of the distal part of theintroducer tube relative to the detached part of the peritoneum to beobserved.

Once the distal part 15 of the introducer tube has been positioned, theseparation component 1 is clamped in position, or is gripped, andinflation fluid is once more passed through the valve 11, and the boreof the introducer tube 3 into the main inflatable chamber 13. The mainenvelope 12 expands once more, increasing the extent of the detachedpart of the peritoneum towards the groin, as shown in FIG. 10F. Theincreased extent of the detached part of the peritoneum is indicated bythe line DP' in the figure. It should be noted that the extent of thedetached part of the peritoneum is increased in the direction from theumbilicus to the groin, but not in the direction transverse to thisdirection. The endoscope E is used to observe the extent of theseparation.

The process of collapsing the main envelope 12, advancing the distalpart 15 of the introducer tube to the limit of the detached part of theperitoneum DP, in the direction of the groin, holding the introducertube in position, and partially re-inflating the main envelope 12, isrepeated until the detached part of the peritoneum includes theperitoneum over the site of the hernia. This process provides the tunnelT between the incision at the umbilicus and the site of the hernia. Thiscan be seen in FIG. 10I. Alternatively, the main envelope can be fullyre-inflated.

When the main envelope is in the vicinity of the site of the hernia H,the main envelope 12 is fully inflated to form a working space WSincluding the site of the hernia. This is shown in FIG. 10G.

The working space at the site of the hernia is then insufflated. Withthe two-component apparatus, inflation fluid is vented from the maininflatable chamber 13 to collapse the main envelope 12, and theseparation component 1 is withdrawn from the tunnel T through theincision I. The insufflation component 21 is introduced into theincision, and advanced through the tunnel until the envelope 45 of thetoroidal inflatable chamber 43 lies within the working space WS, clearof the tunnel. The toroidal inflatable chamber is inflated, the anchorflange is clamped in position, and insufflation gas is passed into theworking space, as shown in FIG. 10H. The toroidal inflatable chamberprovides a gas-tight seal with the entrance of the tunnel.

FIG. 10I shows a plan view of the abdomen with the insufflator component21 in place. The anchor flange has been omitted for clarity. Thetoroidal inflatable chamber 43 provides a gas-tight seal with theentrance of the tunnel T. The extent of the separated peritoneum isindicated by the dotted line DP. It can be seen that the lateral extentof the separated peritoneum is considerably greater in the working spaceWS than in the tunnel T.

With the first embodiment of the one-component apparatus, inflationfluid is vented from the main inflatable chamber to collapse the mainenvelope, and the main envelope is withdrawn from the working spacethrough the bore of the tube assembly. The tube assembly is partiallywithdrawn until the envelope of the toroidal inflatable chamber lieswithin the working space, clear of the entrance to the tunnel. Thetoroidal inflatable chamber is inflated, the anchor flange is clamped inposition and insufflation gas is passed into the working space, asalready described. The toroidal inflatable chamber seals against theentrance from the tunnel into the working space.

Using the second embodiment of the one-component apparatus, the mainenvelope is preferably returned to a partially collapsed state, the tubeassembly is partially withdrawn until the main inflatable chamber lieswithin the working space, adjacent to the entrance of the tunnel. Theanchor flange is clamped in position, and insufflation gas is passedinto the working space, as already described. The partially-collapsedmain chamber seals against the entrance from the tunnel into the workingspace.

If the main envelope is inflated to a fully expanded state during theseparation part of the procedure, the whole of the space is insufflatedwith a gas-tight seal at the incision, as previously described.

Irrespective of the embodiment of the apparatus used to create theinsufflated working space WS, the hernia is then repaired using theprocedure described in connection with FIG. 3I.

5. INFLATABLE CHAMBERS FOR MAINTAINING SEPARATION OF TISSUE LAYERS

As previously discussed, during dissection of the properitoneal space orduring subsequent surgical procedures near the peritoneum, it is commonto puncture or otherwise breach the peritoneum. Such a puncture orbreach prevents the properitoneal space from retaining pressurized fluid(gas or liquid) used to maintain the space in an open condition. Ifpressure is lost, visualization of the space and the actual volume ofthe space will decrease and compromise the surgery. Absent some way ofmechanically maintaining the space, loss of pressure can result ininability to complete the procedure.

An additional consideration in laparscopic surgery inside the peritonealspace is fouling of the distal end of the endoscope with body fluidscaused by incidental contact with either tissues near the entry point ofthe endoscope or tissues near the distal end of the cannula throughwhich the endoscope has been inserted.

(a) First Inflatable Chamber

Referring to FIGS. 11A and 11B, an insufflation and retraction device301 having a first inflatable chamber 303 is shown. The insufflation andretraction device 301 is similar to the insufflation component 21 of thetwo-component apparatus, shown in FIGS. 2D and 2E, and like referencenumerals represent like components. It is understood that although it ispreferred to use the inflatable chambers described below with theinsufflation and retraction device 301, the inflatable chambers may alsobe used with any other delivery or inflation device.

The insufflation and retraction device 301 includes an inner tube 335and a coaxial outer tube 337. The distal end 323 of the inner tube 335extends beyond the distal end 325 of the outer tube 337. The inner tube335 is similar to the introducer tube 3 (FIG. 2A) and is a rigid tubehaving a bore with a circular cross section that can preferablyaccommodate a 10 mm endoscope, however, any cross-sectional shape orarea may be provided. The proximal end of the inner tube 335 is fittedwith a flapper valve as described above in connection with theinsufflation component of FIGS. 2D and 2E. A seat at the proximal end ofthe inner tube forms a gas-tight seal with an appropriately sizedinstrument. A shutter covers the seat and is operated by a button 329. Ablunt obturator 322 is shown extending through the seat and through thedistal end 323 of the inner tube 335 (FIGS. 11A and 11B). A valve 331 isfluidly coupled to the interior of the inner tube 335 and may be used tosupply insufflation gas or liquid.

The first inflatable chamber 303 has a distal side 343 coupled to theinner tube 335 and a proximal side 345 coupled to the outer tube 337 sothat the interior of the inflatable chamber 303 is fluidly coupled tothe annular space between the inner and outer tubes 335, 337. Theproximal and distal sides 345, 347 of the inflatable chamber 303 arepreferably attached to the inner and outer tubes 335, 337 at flanges359. A valve 353 is adapted to be connected to a source of a suitableinflation gas or liquid (not shown) for inflating the inflatable chamber303. The inflatable chamber 303 is shown in a collapsed state in FIG.11A and in an expanded state in FIGS. 11B and 11C.

An anchor flange 355 is slidably mounted to the outer tube 337 and canbe locked along the length of the outer tube 337 with a locking lever349. The anchor flange 355 helps to immobilize the device and, further,helps the inflatable chamber 303 form a seal to limit the escape ofinsufflation gas during laparoscopic procedures. When the anchor flange355 is locked into position, the anchor flange 355 and inflatablechamber 303 apply a modest compressive force to the tissue between theinflatable chamber 303 and the anchor flange 355 thereby improving thegas-seal.

Referring to FIG. 11A, the inflatable chamber 303 is folded andcontained within a sheath 349 before insertion into a patient. Theinflatable chamber 303 may be folded in any manner but is preferablyfolded inwardly from lateral, side edges 351, 353 toward the extendeddistal end of obturator 322. The sheath 349 is preferably perforated butmay be formed in any other manner permitting easy opening. Theinflatable chamber 303 is initially in the folded, compact orientationof FIG. 11A before insertion into the patient so that the retractiondevice may be easily inserted through a small opening in the patient. Aswill be described below, after the inflatable chamber 303 has beenpositioned within a patient and between the two tissue layers to beseparated, inflation air is injected into the inflatable chamber 303through the second valve 353. Inflation of the chamber 303 tears thesheath 349 along the perforation 361 and releases the inflation chamber303. Alternatively, the sheath 361 may include an independent openingmechanism, such as a removable thread which binds the sheath together.

Referring to FIG. 11C, the inflatable chamber 303 preferably has asubstantially trapezoidal shape. First and second sides 363, 365 of theinflatable chamber 303 are preferably slightly curved but may also belinear or bi-linear. The first and second sides 363, 365 and lateralsides 351, 353 may also include surface features such as ridges orrounded teeth to help anchor the inflatable chamber 313 and improve theinsufflation gas seal. The second side 365 is preferably longer than thefirst side 363 and forms angles of less than 90 degrees with the lateralsides 351, 353. Furthermore, the inner and outer tubes 335, 337 arepreferably connected to the inflatable chamber 303 closer to the firstside 363 than the second side 365. A throughhole 358 is defined by theouter tube and extends through the first and second sheets. The shape ofinflatable chamber 303 may also be modified and/or optimized to suit theparticular use contemplated. The location and configuration of thethroughhole 358 may also be modified.

The inflatable chamber 303 is formed with first and second sheets 367,369 attached together along a periphery 371. This arrangement results inrelatively high localized stress at the periphery 371 of the first andsecond sheets 367, 369. To withstand this stress, the strength of thesheets must be increased. One way of increasing the strength of thesheets is to increase the thickness of the sheets. A problem with simplyincreasing the sheet thickness is that the inflatable chamber 303becomes larger in the collapsed state (FIG. 11A) which will causes moreproblems during insertion into a patient.

To alleviate the problem of localized stresses without increasing thesheet thickness, the present invention provides baffles 373 disposedbetween the first and second sheets 367, 369. The baffles 373interconnect the first and second sheets 367, 369 and help absorb thepressure forces thereby reducing stresses at the periphery 371. Thebaffles 373 also help define the shape of the inflatable chamber 303 andlimit the separation distance between the first and second sheets 367,369 when the inflatable chamber 303 is in the expanded shape. Thepreferred method of attaching the baffles 373 to the first and secondsheets 367, 369 is described below.

(i) Preferred Material for the Inflatable Chamber

The first and second sheets 367, 369 and baffles 373 are preferably madeof a polyester and polyurethane composite material. Polyester hasdesirable strength characteristics but it is relatively rigid andcrinkles easily. Moreover, polyester is very difficult to RF weld whichis a preferred method of connecting the baffles and sheets together aswill be described below. Polyurethane, on the other hand, is soft,non-abrasive, and easy to RF weld. Unfortunately, the tensile strengthof polyurethane is relatively low. The composite material exploits theadvantages of both polyester and polyurethane.

The composite material is formed by bonding polyurethane to a nylon orpolyester film having a preferred thickness of about 0.5 to 2 mil.(12-50 μm), although a polyester fabric may also be used. The nylon orpolyester fabric may be a woven fabric or may be composed ofrandomly-oriented fibers. The film or fabric layer is laminated (orcast, captured or encapsulated) between two polyurethane layers toprovide a composite material having a preferred thickness of about 3mil. (75 μm). The resulting composite material is strong, supple,non-abrasive, transparent, and easily RF welded. The composite materialwill also fold with small radius folds so that the inflatable chamber303 can be compacted into a small volume for easy insertion into apatient.

The composite material is relatively inelastic and, therefore, must befolded into the sheath as described above (FIG. 11A). The presentinvention may also be practiced with an elastic material which, whenexpanded, provides the shape of the inflatable chambers of the presentinvention. The composite material is disclosed in co-pending U.S. patentapplication Ser. No. 08/134,573, filed Oct. 8, 1993, which is hereinincorporated by reference.

(ii) Method of Constructing the Inflatable Chamber

The baffles 373 are preferably fabricated and attached to the first andsecond sheets 367, 369 in the manner shown in FIGS. 13A through 13C. Thefirst and second sheets 367, 369 and baffles 373 are cut into thedesired shape and oriented as shown in FIG. 13A with the first andsecond sheets 367, 369 being offset with respect to one another. Thebaffles preferably do not extend completely between the first and secondsides so that all portions of the interior of the inflatable chamber arefluidly coupled together. Alternatively, the baffles 373 may includeopenings to fluidly couple the various portions together. The baffles373 are preferably made of the same material as the first and secondsheets but may also be made of a different material.

Referring to the exploded cross-sectional view of FIG. 13B, RF weldingelectrodes 344, 346 are positioned against the first and second sheets367, 369. RF welding imparts radio frequency energy to the workingpiece. When radio frequency energy is imparted onto polyurethane, themolecules are excited and the polyurethane melts thereby bondingtogether adjacent polyurethane layers together. A suitable release agent305 is applied to either the sheets 367, 369 or baffles 373 to preventformation of RF welds at certain locations. A preferred release agent305 is powdered polyethylene and teflon. Without the releasing agent305, the baffle 373 would be RF welded to both the first and secondsheets 367, 369 on both sides. Application of the release agent 305advantageously enables attaching the baffles 373 to the sheets in asingle welding operation.

The RF welding apparatus is activated to weld the baffles 373 to thefirst and second sheets 367, 369. Adjacent polyurethane layers bond atall locations between the RF welding electrodes 375 except where therelease agent 305 has been applied. The first and second sheets are thendisplaced so that they overlie one another as shown in FIG. 13C. Theresulting baffles 373 have a generally S-shaped configuration when theinflatable chamber is in the expanded condition. A second RF weldingoperation (not shown) welds the periphery 371 of the first and secondsheets together 367, 369.

(b) Second Inflatable Chamber for Maintaining Separation of TissueLayers

A second inflatable chamber 403 for maintaining separation betweentissue layers is shown in FIGS. 12A and 12B. The second inflatablechamber 403 includes an intermediate weld 405 which reduces pressureinduced stresses at the periphery 471 of the inflatable chamber 403. Theintermediate weld 405 eliminates the need to provide baffles, however,baffles may also be provided if necessary. The intermediate weld 405 ispreferably a semi-circular segment having terminal ends 407 positionedadjacent the periphery 471. An interior area 411 is fluidly coupled tothe remainder of the inflatable chamber 403 via two fluid paths 413 sothat when the inflatable chamber 403 is inflated, the interior area 411is also inflated. The fluid paths 413 are preferably provided betweenthe terminal ends 407 of the intermediate weld 405 and the periphery471; however, the fluid path 413 may be positioned anywhere along theintermediate weld 405. Furthermore, although it is preferred to providetwo fluid paths, any number of paths may be provided.

The periphery 471 of the inflatable chamber 403 is substantiallybell-shaped with the hemispherical interior area 411 protruding slightlyfrom a bottom side 413. The bell-shaped periphery 471 has asemi-circular upper portion 415 which is substantially concentric with athroughhole 417. The remainder of the peripheral wall 471 is shaped likea truncated triangle extending downward from the semi-circular upperportion 415. As previously described, the shape of the inflatablechamber may be modified to suit the particular use contemplated.Materials and construction techniques are as described previously.

(c) Third Inflatable Chamber for Maintaining Separation of Tissue Layers

Referring to FIGS. 14A and 14B, a third inflatable chamber 503 is shownwhich also includes intermediate welds 505. The inflatable chamber 503is advantageously formed from only first and second sheets 567, 569 ofmaterial. The intermediate welds 505 are preferably circular but maytake any other shape. The intermediate welds bond the first and secondsheets 567, 569 together throughowelds. Before insertion into apatiewelds. Before insertion into a patient, the inflatable chamber 504is preferably folded and contained within a perforated sheath asdescribed above in connection with the first inflatable chamber 303.

The inflatable chamber 503 has a substantially trapezoidal shapedperiphery 571. The sides 507, 509, 511, 513 of the inflatable chamberare preferably linear but may also be curved. A first side 507 issmaller than a second side 509 and the second side preferably forms anangle of between 20 and 90 degrees with the lateral sides 511, 513.

(d) Fourth Inflatable Chamber for Maintaining Separation of TissueLayers

Referring to FIGS. 15A and 15B, a fourth inflatable chamber 603 is shownwhich has the same general features as the second inflatable chamber403, however, inflatable chamber 603 includes first and secondextensions 621, 623 having a space 633 therebetween. The space 633provides clearance for insertion of additional instruments into theworking space while minimizing the risk that the additional instrumentswill pierce the inflatable chamber 603 as described below. A throughhole617 extends through the inflatable chamber 603 which is adapted to beconnected to the insufflation component of FIGS. 11A and 11B or may beconnected to any other delivery or inflating device.

The fourth inflatable chamber 603 is preferably symmetrical about a lineof symmetry 609 passing through the throughhole 617. First and secondperipheral points 625, 627 are located on the line of symmetry 609 withthe first peripheral point 625 being closer to the throughhole 627 thanthe second peripheral point 627. The first and second extensions 621,623 have radially outward points 629, 631. A line 630 passing throughthe center of the throughhole 617 and the radially outward to points629, 631 preferably forms an angle A between 10 degrees and 80 degreeswith respect to a line 632 extending between the throughhole and thefirst peripheral point 625. The extensions are preferablytriangular-shaped with rounded edges but may also take any other shapeso long as the space 633 is provided therebetween. Furthermore, thespace 633 is also preferably triangular shaped but may also besemi-circular, square, or a relatively shallow circular segment.Modifications to the proportions illustrated as well as providingasymmetrical designs are also contemplated to suit the particularapplication.

During laparoscopic surgery, additional instruments are often introducedabove the longitudinal axis of the delivery device. The space 633between the extensions 621, 623 facilitates introduction of additionalinstruments along the longitudinal axis of the delivery device above theinflatable chamber 603 while minimizing the risk that the additionalinstruments will puncture the inflatable chamber 603.

The inflatable chamber 603 is preferably formed from first and secondsheets 667, 669 of the composite material described above but may beformed in any other manner or with any other materials to provide theextensions 621, 623 and space 633 therebetween. The first and secondsheets 667, 679 are preferably attached together about the periphery 671by RF welding as described above. The first and second sheets 667, 669are also preferably coupled together by an intermediate weld 605. Theinflatable chamber 603 may also be formed with baffles or with a sheetmaterial of sufficient thickness to withstand the stress at theperiphery 671.

(e) Fifth Inflatable Chamber for Maintaining Separation of Tissue Layers

Referring to FIGS. 16A and 16B, a fifth inflatable chamber 703 is shownwhich is an alternative to inflatable chamber 303 of FIGS. 11B through11C. The fifth inflatable chamber 703 may be used with any inflation ordelivery device but is preferably used in connection with theinsufflation component of FIGS. 2D and 2E or FIGS. 11A and 11B.

The fifth inflatable chamber 703 has essentially the same structuralfeatures as the first inflatable chamber 303, however, the inflatablechamber 703 includes a pair of triangular-shaped wings 705. Thetriangular wings 705 provide a wider working space within the patientthan the inflatable chamber 303. The wings 705 may also advantageouslyprovide additional tissue dissection when the chamber 703 is inflated.

Inflatable chamber 703 is preferably made from the same or likematerials as inflatable chamber 303 and, furthermore, is constructedwith baffles 707 in the same manner as inflatable chamber 303.

For the first, second, third, fourth and fifth embodiments of theinflatable chamber described above, it should be recognized that theshape of each embodiment has the common functional benefit ofmaintaining the properitoneal space by retaining the separation of theperitoneum from the overlying tissue in the event of loss of optimalpressurization or when a gasless technique is used.

More specifically, the embodiments each employ a bottom surface whichcontacts the peritoneum and an upper surface that contacts the overlyingfascia. For example, in the first embodiment shown in FIG. 11C, theupper surface can be characterized as side 363 and the lower sidecharacterized as side 365. The physical distance between the upper andlower surfaces causes like separation or the peritoneal layer and fascialayers in the dissected properitoneal cavity. The inflatable chamber canbe dimensionally sized to create optimal separation while limitingpotential trauma to tissue. Furthermore, the location of throughhole 358within the inflatable chamber can be selected to optimize the separationof retracted tissue from an endoscope or other instrument passed throughthroughhole 358. Throughhole 358 thus can be centered or off-center inthe inflatable chamber as desired. Preferably, throughhole 358 islocated slightly off-center towards the upper surface, but centeredlaterally. Such a location optimizes the desired features of reducingendoscope fouling by body fluids as the scope is passed into throughhole358, and separating the scope from the peritoneum to provide maximumviewing field with a scope through throughhole 358. The reduction offouling is accomplished by displacing the throughhole 358 from the uppersurface, and thus overlying fascia, to minimize potential tissue contactwith throughhole 358 and an endoscope passed through throughhole 358.Likewise, the viewing field is maximized by separating throughhole 358,and thus an endoscope in it, from peritoneum being deflected downward bythe lower surface of inflatable chamber.

6. HERNIA REPAIR METHOD WITH INCISION AT THE UMBILICUS

The hernia repair method described above in connection with theinsufflation component having the toroidal inflatable chamber will knowbe described with respect to the fourth inflatable chamber 603 describedabove. It is understood that the following method may be practiced usingany of the inflatable chambers 303, 403, 503, 603, 703.

Referring to FIGS. 17A and 17B, an incision 801 is made at or near theumbilicus and a tunnel 803 is formed from the incision toward the siteof the hernia. The peritoneum P is then dissected from the underlyinglayer U. The tissue layers are preferably dissected with the apparatusand methods described above; however, dissection may also beaccomplished in a conventional manner. For example, dissection may beaccomplished with an endoscope, graspers, an operating scope or anyblunt instrument which may be used to dissect the tissue layers bysweeping the area between the layers.

Once the tissue layers have been dissected, the retraction device isinserted through the tunnel 803 while in the compact deflated conditionof FIG. 11A. When the inflatable chamber 603 is within the working spaceWS, an inflation fluid (any suitable gas or liquid, such as air orsaline) is injected into the inflatable chamber 603 thereby expandingthe inflatable chamber to the shape of FIG. 17A. A conventional handbulb or syringe can be used to inject the fluid through port 353. Theanchor flange 655 is moved toward the distal end and locked in positionso that a compressive force is exerted on the abdominal wall by theanchor flange 655 and inflatable chamber 603. The compressive forceensures that the inflatable chamber 603 forms a seal which inhibits theescape of insufflation gas through the tunnel 803. Insufflation gas isthen passed into the working space WS and the hernia H is then repairedusing the procedure described in connection with FIG. 31. During repairof the hernia, an additional instrument I may be introduced into theworking chamber in the space 633 between the extensions 629, 631. Thespace 633 permits introduction of the additional instrument I whileminimizing the risk that the additional instrument I might puncture theinflatable chamber 603.

7. METHOD AND APPARATUS FOR PACKING DEFLATED BALLOONS

As mentioned above, a known method of packing inflatable balloons is toroll the balloon inward from opposing sides of the chamber as shown inFIG. 18. A problem which occurs during inflation of the balloon packedin the known manner of FIG. 18 is that unrolling of the balloon cancause trauma to the tissue layer due to differential motion between thetissue layer and the balloon. Referring to FIG. 19, a balloon 807compacted in the known manner of FIG. 18 is in a partially inflatedstate. During inflation, rolls 809 displaces outwardly with a top edge811 rubbing against the upper tissue layer 813 which can cause trauma tothe tissue layer.

The problem of traumatizing the tissue layers is particularlyproblematic when using an inflatable balloon in the properitoneal space.If the peritoneum is punctured or otherwise breached due to a tearcaused by unrolling of the balloon, the properitoneal space cannotretain pressurized fluid to maintain the space. If pressure is lost, thevolume of the space will decrease and compromise the surgery.

Referring to FIGS. 20 and 21, a preferred balloon 901 for dissecting thepreperitoneal space is shown. The balloon 901 has a kidney-beancross-sectional shape as shown in FIG. 21. It is understood that thepresent invention may be practiced using any shape balloon and theballoon 901 is merely an example. For example, the balloon 901 may alsobe spherical, oblong, cylindrical or any other shape suited for theparticular dissection and/or retraction contemplated.

The balloon 901 is preferably mounted to an inflation and deliverydevice as shown in FIG. 2A but may also be attached to any otherinflation and delivery device. The balloon is mounted to an introducertube 903 having a bore 904 with a circular cross-section that canaccommodate an endoscope. The bore 904 houses a fluid path 906 forinflating the balloon. The proximal end of the introducer tube is fittedwith a port 905 in which is mounted a flapper valve 907. The shutter ofthe flapper valve is operated by a button 909. The flapper valve forms agas-tight seal with an endoscope or other instrument inserted though theflapper valve into the bore of the introducer tube. The port is alsofitted with a valve 911 to which a supply of a suitable inflation fluidcan be connected. The inflation fluid passes through the valve,introducer tube and into the balloon 901.

The balloon 901 is preferably formed from first and second sheets 913,915 in the manner described above in connection with the inflatablechambers of FIGS. 11-16. The balloon 901 is also preferably made of thematerials and fabricated in the manner described above in connectionwith FIGS. 11-16. Other preferred materials include latex, siliconerubber, or polyurethane. Furthermore, although the term balloon is used,the inflatable balloon may be elastic or inelastic.

Referring to FIG. 22, a first portion 917 of the balloon isdisplaced-inwardly toward the interior of the balloon in accordance witha preferred method of packing the balloon. Although it is preferred todisplace the first portion 917 of the balloon in a directionperpendicular to a longitudinal axis 919 of the introducer tube 903, theballoon 901 may also be displaced inwardly in any other direction.

The first inwardly-displaced portion is then preferably rolled-up withinthe interior of the balloon with a rolling device 921 inserted throughthe bore of the introducer tube 903. Referring to FIGS. 23 and 24, therolling device 921 includes two rolling rods 923 for grasping the firstinwardly-displaced portion 917. Each rod 923 has a diameter of about 1/8inch and a gap of preferably less than 1/16 inch therebetween. The gapsize and diameter of the rods 923 may vary, of course, depending on thethickness of the balloon material. Furthermore, the rolling device 921may include any other feature for grasping the inwardly displacedportion, such as a pair of jaws, a clamp or a pair of elasticallydeformable arms. The rolling device has a knurled handle formanipulating the rolling device.

The rolling device 921 is rotated to roll the first portion as shown inFIG. 25. After the first portion has been rolled into a sufficientlycompact roll, a second portion of the balloon is displaced inwardly androlled in the same manner. The two rolls 929, 931 are then housed withina sheath 933 as described above in conjunction with the inflatablechambers of FIGS. 11-16. An obturator 935 is positioned in the bore ofthe introducer tube and between the two rolls 929, 931 to providestructural support for the balloon 901 during insertion into thepatient. The obturator 935 is also shown in FIGS. 2E, 11A and 11B. Therolls 929, 931 are positioned on opposite sides of the obturator 935with the obturator 935 including concave portions 937 for receiving therolls 929, 931.

The compact, deflated balloon is introduced into the patient between thetwo tissue layers to be separated and is then inflated. The balloon 901may be used for dissecting and/or retracting tissue planes throughoutthe body. Referring to FIG. 27 which shows the balloon during inflationin the peritoneum, the inwardly-displaced portions evert duringinflation so that differential motion between the balloon 901 andadjacent tissue layers 937 is minimized thereby reducing trauma to thetissue layers.

Although it is preferred to roll the first and second inwardly-displacedportions into first and second rolls 929, 931 within the interior of theballoon 901, the balloon 901 may be packed in any other manner so longas an inwardly-displaced portion is provided which everts duringinflation. Referring to FIGS. 28 and 29, the inwardly-displaced portions917, 927 may also be displaced to a side opposite the initialdisplacement and then rolled-up into the rolls as previously described.

The first and second inwardly-displaced portions 917, 927 may also berolled in the conventional manner from opposing lateral sides afterdisplacing the portions inward as shown in FIGS. 30 and 31. The firstand second portions 917, 927 divide the balloon 901 into an upper part939 and a lower part 941. The upper part 939, first portion 917 andlower part 941 are then rolled-up in the conventional manner as shown inFIG. 31. When the balloon 901 is rolled in the manner shown in FIG. 30and 31, the balloon 901 will suffer the problem of relatively highdifferential motion between the balloon 901 and the adjacent tissuelayer during the initial inflation and deployment, however, during theend of the inflation, the balloon will have relatively low differentialmotion relative to the tissue layers. This method of packing a balloonis useful when problematic internal structures are positioned laterallyoutward from the obturator.

When the balloon is formed from first and second sheets 913, 915, theupper and lower parts are preferably formed by the first and secondsheets 943, respectively. By configuring the balloon 901 in this manner,the first and second portions include a part of the seam 943 between thefirst and second sheets 913, 915. When coupling the first and secondsheets 913, 915 together with an RF weld, the seam 943 forms arelatively thin, rigid periphery which can cut or otherwise traumatizethe tissue layers. Referring to FIG. 27, the seam 943 everts into aspace 945 between the tissue layers along the lateral edges of theballoon 901 thereby minimizing contact between the seam 943 and thetissue layers.

The balloon 901 may also include a number of inwardly-displaced portionsin the form of accordion-folds 947 as shown in FIGS. 32. FIG. 33illustrates the balloon of FIG. 32 in the compact, deflated state.

Although individual preferred embodiments have been described, theinvention may be practiced using any combination of preferred features.For example, a small roll may be formed in the manner shown in the FIGS.23 and 25 followed by the procedure shown in FIG. 31.

8. BALLOON CANNULA SYSTEMS

As mentioned above, a known method of attaching an inflatable balloon toa delivery device is to attach the balloon to the distal end of acannula. A problem which can occur during inflation of the balloon isthat the balloon can become skewed and off-center as shown in FIG. 34.The balloon becomes skewed and off-center since the balloon is notsupported during inflation and becomes skewed due to the forces impartedon the balloon by the adjacent tissue layers.

Another known method of attaching a balloon to an inflation and deliverydevice is to mount the balloon to the delivery device away from thedistal end of the cannula so that the cannula extends into the interiorof the balloon. The cannula provides structural support for the balloonduring inflation as shown in FIG. 35. A problem which occurs whenmounting the balloon away from the distal end of the cannula is that thevisual field of an endoscope inserted in the device is limited. Theendoscope has a blind area behind the distal end of the cannula (FIG.35).

The balloon cannula systems of the present invention provide asupporting a portion which extends into the interior of the balloon toprovide support for the balloon during inflation. After inflation of theballoon, the supporting part is removed from the interior of the balloonso that an endoscope inserted into the interior of the balloon has avisual field which is not limited as described above. The ballooncannula systems described herein may be used in any procedure requiringdissection and/or retraction of tissue planes throughout the body.

A. First Balloon Cannula System

Referring to FIG. 36, a first balloon cannula system 948 is shown. Thefirst balloon cannula system 948 includes a delivery device 949 and aninsert 950. An outer cannula 951 is mounted to the delivery device 949and an inner cannula 952 is mounted to the insert 950. An obturator 33,as described above, is also provided but is not necessary for practicingthe invention.

The delivery device 949 is preferably the same as described above inconjunction with FIGS. 2A, 2D, 2E, 11A, and 11B and the same referencenumbers refer to the same items. The delivery device 949 includes aninflation port 953 for inflating a balloon 954 mounted to a distal endof the outer cannula 952. A button 9 operates a flapper valve 6 which isdescribed above in conjunction with FIG. 2A. The flapper valve 6 seals aport 955 having a first elastomeric member 956 mounted thereto. Althoughit is preferred to use the delivery and inflation device of FIG. 2A, anyother inflation or delivery device may be used.

The balloon 954 preferably has a substantially spherical shape wheninflated. It is understood that the present invention may be practicedusing any shape balloon and the spherical balloon 954 is merely anexample. For example, the balloon may be oblong, cylindrical or anyother shape suited for the particular dissection and/or retractioncontemplated. The balloon 954 is preferably made of the materialsdescribed above. The balloon 954 is preferably packaged in a sheath asdescribed above, however, the balloon 954 may also be packaged in anyother manner.

Referring to FIG. 38, the insert 950 has an opening 957 at a proximalend which leads to an interior of the inner cannula 952. A clasp 958 isprovided at the proximal end for locking the insert 950 to aninstrument, such as an endoscpoe, passing through the opening 957. Theclasp 958 preferably includes a simple over-center action locking lever959. The opening 957 includes a second elastomeric member 960 whichprovides a substantially fluid tight seal with an appropriately sizedinstrument passing through the opening 957. The second elastomericmember 960 and instrument are preferably sized so that the fluid tightseal is maintained even when the instrument is displaced longitudinallyrelative to the insert 950.

A stop 961 is preferably attached to the distal end 962 of the innercannula 952. The stop 961 ensures that the endoscope will be recessedfrom the distal end 962 of the inner cannula 952 as will be described ingreater detail below. Referring to FIG. 41, the stop 961 preferably hasan opening 963 which tapers inwardly toward the distal end 962 and issized smaller than the distal end of the endoscope.

The inner cannula 952 includes a supporting portion 964 which supportsthe balloon 954 during inflation so that the balloon 954 does not becomeskewed and off-center. The supporting portion 964 is movable between anextended position, in which the supporting portion 964 extends into aninterior 965 of the balloon 954 as shown in FIG. 41, and a retractedposition, in which the supporting portion 964 is outside the interior965 of the balloon 945 and housed within the outer cannula 951 as shownin FIG. 42.

The insert 950 and delivery device 949 are preferably configured toengage one another with a locking engagement. FIG. 37 shows an end viewof the delivery device 949 and the insert 950. The insert 950 preferablyincludes a pair of lips 966 which engage recesses 967 in the deliverydevice 949. The insert 950 and delivery device 949 are coupled togetherand then rotated so that the lips 966 engage the recesses 967 therebylocking the insert 950 to the delivery device 949. The insert 950 anddelivery device 949 may also engage one another in any other manner knowto one having ordinary skill in the art, such as with a bayonet,cam-lock, or threaded connection.

The outer diameter of the inner cannula 952 is preferably sized toengage the first elastomeric member 956 to provide a substantially fluidtight seal therebetween. The fluid tight seal permits slidable movementbetween the insert 950 and the delivery device 949. The outer and innercannulas 951, 952 are slidably movable relative to one another so thatthe supporting portion 964 is movable between the extended and retractedpositions.

Operation of the first balloon cannula system 948 will now be described.Before being inserted into a patient, the first balloon cannula system948 is configured as shown in FIG. 39. The inner cannula 952 is insertedthrough the port 955 in the delivery device 949 so that the supportingportion 964 of the inner cannula 952 extends beyond the distal end ofthe outer cannula 951 and into the interior 965 of the balloon 954. Thesupporting portion 964 of the inner cannula 952 extends beyond thedistal end of the outer cannula 951 and provides support for the balloon954 during inflation. The supporting portion 964 preferably extends atleast half way to an opposing side 968 of the balloon 954 and morepreferably extends at least three quarters the distance to the opposingside 968 of the balloon.

The insert 950 is then locked to the delivery device 949 by rotating theinsert 950 so that the lips 966 engage the recesses 967. The obturator33 is inserted through the opening 957 in the insert 950 and the clasp958 is locked to lock the obturator 33 to the insert 950. The obturator33 preferably has a blunt tip extending beyond the distal end of theinner cannula 952. The blunt tip reduces trauma to the patient when theballoon 954 is inserted into the patient. The blunt tip also preventsdamage to the balloon 954 which might occur with a conventional trocaror other instrument.

The balloon 954 is then advanced in the patient until the balloon 954 isin the desired position for dissection and/or retraction. The clasp 958is unlocked and the obturator 33 is removed. An endoscope E isintroduced through the opening 957 in the insert 950 until the endoscopeE contacts the stop 961. The stop 961 is preferably configured so thatthe distal end of the endoscope E is recessed from the distal end of thestop 961 between 2 mm and 10 mm and more preferably about 5 mm. Byrecessing the endoscope E from the distal end of the inner cannula 952,the endoscope E can visually access the tissue in contact with theballoon 954 without abutting against the inner surface of the balloon954 and obscuring visualization.

A suitable inflation device is then attached to the inflation port 953and a suitable inflation fluid is used to inflate the balloon 954.During inflation, the supporting portion 964 advantageously providessupport for the balloon 954 so that the balloon 954 does not becomeskewed and off-center. The inflation fluid enters the balloon 954through a fluid path 969 at least partially contained within the outercannula 951. The term fluid path 969 as defined herein, refers to anystructure which fluidly couples the inflation port 953 and the interior965 of the balloon 954. For example, the fluid path 969 may be a tubewhich is separate from the inner and outer cannulas 952, 951. Apreferred inflation device is a bulb (not shown) which delivers acontrolled volume of the inflation fluid with each squeeze. A gas,preferably air, is the preferred inflation fluid, but other gases, suchas carbon dioxide, can be used. A liquid, such as saline solution, canalso be used, however, such liquids are less preferable because theychange the optical properties of the endoscope E.

The insert 950 is then unlocked from the delivery device 949 by rotatingthe insert 950 to disengage the lips 966 from the recesses 967. Theendoscope E remains locked to the insert 950 with the clasp 958 and,therefore, the endoscope E and insert 950 act as a single unit.Referring to FIG. 42, the insert 950 may be moved longitudinally in thedirection of arrow A--A to provide optimal visualization of the tissue.The insert 950 is longitudinally movable so that the supporting portion964 is movable between the extended and retracted positions. Duringmovement between the extended and retracted positions, the inflationfluid is maintained in the balloon 954 by virtue of the substantiallyfluid tight seal between the first elastomeric member 956 and the insert950. Supplemental inflation fluid can be provided through the inflationport 953 as necessary to make up for any fluid losses past the firstelastomeric member 956.

B. Second Balloon Cannula System

Referring to FIGS. 43 through 45, a second balloon cannula system 948Ais shown which includes a delivery device 949A and an outer cannula951A. Reference numerals with an added "A" represent items similar tothose described above in conjunction with the first balloon cannulasystem 948. An inner cannula 952A is mounted to the delivery device 949Aand the outer cannula 951A is slidably mounted to the inner cannula952A. The balloon 954, as described above, is mounted to the distal endof the outer cannula 951A.

The delivery device 949A is preferably the same as the delivery device949 described above in conjunction with the first balloon cannulasystem. The inner cannula 952A has the stop 961 attached to the distalend. The delivery device 949A includes the inflation port 953 and button9 which activates a flapper valve (not shown). The inflation port 953 isfluidly coupled to the interior 965 of the balloon 954 via a fluid path969A at least partially defined by an interior 971 of the inner cannula952A (FIG. 45). The fluid path 969A may take any form so long as itfluidly couples the interior 965 of the balloon 954 to the inflationport 953.

The outer cannula 951A is slidably mounted to the inner cannula 952Abetween an extended position, in which a supporting portion 964A of theinner cannula 952A extends into the interior 965 of the balloon 954 asshown in FIG. 43, and a retracted position, in which the supportingportion 964A of the inner cannula 952A is outside the interior 965 ofthe balloon 954 as shown in FIG. 44. Referring to FIG. 43, thesupporting portion 964A preferably extends at least half the distance tothe opposing side 968 of the balloon 954 and more preferably at leastthree quarters the distance to the opposing side 968.

The outer cannula 951A may be slidably coupled to the inner cannula 952Ain any manner but is preferably slidably coupled to the inner cannula952A via a sleeve 972. Referring to the exploded cross-sectional view ofFIG. 45, the sleeve 972 includes a cavity 973 which receives a firsto-ring 974. The first o-ring 974 provides a substantially fluid tightseal between the sleeve 972 and the inner cannula 952A so that inflationfluid pressure is maintained in the balloon 954. The sleeve 972 alsoincludes a detent 975 on each side of the first o-ring 974. One ofdetents 975 engages one of lock rings 976 attached to the inner cannula952A to lock the outer cannula 951A in either the retracted positionshown in FIG. 45 or the extended position relative to the inner cannula952A. The lock rings 976 include a depression 977 sized to matinglyengage the detent 975. As shown in FIG. 45, the outer cannula 951A islocked to the inner cannula 952A in the retracted position. The outercannula 952A may be locked to the inner cannula 951A in any other mannerknown to one having ordinary skill in the art, for example, with abayonet, cam-lock or threaded connection.

Operation of the second balloon cannula system 948A will now bedescribed. Before being inserted into a patient, the second ballooncannula system 948A is configured in the extended position of FIG. 43with the supporting portion 964A of the inner cannula 952A extendingbeyond the distal end of the outer cannula 951A and into the interior965 of the balloon 954. The balloon 954 is deflated and preferablypacked in a sheath (not shown) as described above. The detent 975 of thesleeve 972 is engaged with the depression 977 in the lock ring 976thereby locking the outer cannula 951A in the extended position. Anobturator (not shown) as described above is inserted through the port inthe delivery device 949A with the blunt tip of the obturator extendingbeyond the distal end of the inner cannula 952A.

The balloon 954 is then inserted into a patient and advanced in thepatient until the balloon is in the desired position for the dissectionand/or retraction contemplated. The obturator is then removed and anendoscope (not shown) is then introduced through the port in thedelivery device until the endoscope contacts the stop 961. The stop 961is preferably configured so that the distal end of the endoscope isrecessed from the distal end of the stop 961 between 2 mm and 10 mm andmore preferably about 5 mm.

A suitable inflation device is then attached to the inflation port 953and a suitable inflation fluid, as described above, is used to inflatethe balloon 954. During inflation, the supporting portion 964Aadvantageously provides structural support for the balloon 964 so thatthe balloon 964 does not become skewed and off-center during inflation.The inflation fluid enters the balloon 964 through the fluid path 969Aat least partially defined by the interior 971 of the inner cannula952A. A preferred inflation device is a bulb (not shown) which deliversa controlled volume of the inflation fluid with each squeeze.

Once the balloon 954 is inflated, the inner and outer cannulas 952A,951A are longitudinally movable relative to one another to provideoptimal visualization of the tissue layers. During relative movementbetween the inner and outer cannulas 952A, 951A, the inflation fluidpressure is maintained in the balloon 954 by virtue of the substantiallyfluid tight seal provided by the first o-ring 974. Supplementalinflation fluid is provided through the inflation port 953 as necessaryto make up for any fluid losses past the first o-ring 974.

B. Third Balloon Cannula System

Referring to FIGS. 46 and 47, a third balloon cannula system 948B isshown. Similar items have the same reference numbers as described abovein conjunction with the first and second balloon cannula systems 948,948A except that a "B" has been added. The third balloon cannula system948B includes a delivery device 949B and inner and outer cannulas 952B,951B mounted to the delivery device 949B. The balloon 954, as describedabove, is mounted to the distal end of the outer cannula 951B. Onceagain, it is understood that the present invention may be practicedusing any shape balloon and the balloon 954 is merely an example. Anobturator (not shown), as described above, is also preferably providedfor the reasons described above in conjunction with the first ballooncannula system 948.

The delivery device 949B is preferably the same as the delivery device949A described above in conjunction with the first balloon cannulasystem 948. The delivery device 948B includes the inflation port 953 andthe button 9 which activates the flapper valve (not shown). Theinflation port 953 is fluidly coupled to a fluid path 969B which is atleast partially defined by an interior 971B of the inner cannula 952Bfor inflating the balloon 954 with a suitable inflation fluid.

The outer cannula 951B includes a contracting portion 978 whichcontracts to change a longitudinal length of the outer cannula 951B. Inthe preferred embodiment the contracting portion 978 includes a numberof deformable, longitudinally-extending segments 979. Referring to FIG.47, the segments 979 are deformable along a fold line 980 so that thesegments 979 bow outward (as shown in FIG. 46) and change the length ofthe outer cannula 951B in the direction of a longitudinal axis 981 ofthe inner cannula 951B. Although it is preferred to provide the segments979, the contracting portion 978 may also be any other conventionalmechanism such as an elastically displacable portion, a telescopingmechanism, or a threaded connection. When the contracting portion 978 isin the retracted position of FIG. 44, a supporting portion 964B of theinner cannula 952B extends beyond the distal end of the outer cannula951B and into the interior 965 of the balloon 954. Referring to FIG. 47,when the segments 979 are deformed along the fold line 980, thesupporting portion 964B is housed within the outer cannula 951B.

Referring to the partial cut-away of FIG. 46, a second o-ring 974B iscoupled to the inner cannula 952B. The second o-ring 974B provides asubstantially fluid tight seal between the inner and outer cannulas952B, 951B so that inflation fluid pressure is maintained in the balloon954.

Operation of the third balloon cannula system 948B will now bedescribed. Before being inserted into a patient, the third ballooncannula system 948B is configured as shown in FIG. 46. The balloon 954is deflated and preferably packed in a sheath (not shown) as describedabove. An obturator (not shown) is inserted through the port in thedelivery device 949B with the blunt tip of the obturator extendingbeyond the distal end of the inner cannula 952B.

The balloon 954 is then inserted into a patient and advanced in thepatient until the balloon 954 is in the desired position for dissectionand/or retraction. The obturator is then removed and an endoscope (notshown) is introduced through port in the delivery device 949B until theendoscope contacts the stop 961 attached to the distal end of the innercannula 952B. The stop 961 is the same as described above in conjunctionwith the first and second balloon cannula systems 948, 948A.

A suitable inflation device is then attached to the inflation port 953and a suitable inflation fluid, as described above, is used to inflatethe balloon 954. During inflation, the supporting portion 964B of theinner cannula 952B provides support for the balloon 954 so that theballoon 954 does not become skewed and off-center. The inflation fluidenters the balloon 954 through the fluid path 969B passing through theinterior 971B of the inner cannula 952B.

The obturator is then removed and an endoscope is inserted into the portin the delivery device 949B. By virtue of the contracting portion 978,the inner and outer cannulas 952B, 951B are longitudinally movablerelative to one another between the extended and retracted positions toprovide optimal visualization of the tissue layers. During movementbetween the extended and retracted positions, the inflation fluidpressure is maintained by the fluid seal provided by the second o-ring974B.

Modification and variation can be made to the disclosed embodimentswithout departing from the subject of the invention as defined by thefollowing claims. For example, although it is preferred to provide asupporting portion which is part of an inner cannula or an outercannula, the supporting portion may also be completely separate from theinner and outer cannulas. Furthermore, although it is preferred toprovide a cylindrical supporting portion, the supporting portion mayalso be flared, conical, asymmetrical, or any other shape appropriatefor the particular balloon shape and medical procedure.

We claim:
 1. A device for separating tissue layers, comprising:adelivery device having an inflation port; a balloon having an interior;a fluid path fluidly coupling the inflation port and the interior of theballoon; an outer cannula having a distal end and a proximal end, theballoon being mounted to the distal end of the outer cannula; an innercannula at least partially disposed within the outer cannula, the innercannula having a supporting portion movable between an extended positionrelative to the outer cannula, in which the supporting portion ispositioned within the interior of the balloon, and a retracted positionrelative to the outer cannula, in which the supporting portion ispositioned outside the interior of the balloon, wherein the innercannula is slidably coupled to the outer cannula so that the supportingportion is movable between the retracted position and the extendedposition relative to the interior of the balloon, and wherein at leastone of the inner and outer cannulas is mounted to the delivery device;and an insert, wherein the inner cannula is a portion of the insert,wherein the outer cannula has an interior and is mounted to the deliverydevice, the delivery device includes a port leading to the interior ofthe outer cannula, and the insert passes through the port, and whereinthe insert includes an opening and a lock, the opening being adapted toreceive an endoscope and the lock being movable between a lockedposition, in which the endoscope is locked to the insert with asubstantially fluid tight seal, and an unlocked position, in which theendoscope is unlocked with respect to the insert so that the endoscopeis slidably movable relative to the insert.
 2. A device for separatingtissue layers, comprising:a delivery device having an inflation port; aballoon having an interior; a fluid path fluidly coupling the inflationport and the interior of the balloon; an outer cannula having a distalend and a proximal end, the balloon being mounted to the distal end ofthe outer cannula; an inner cannula at least partially disposed withinthe outer cannula, the inner cannula having a supporting portion movablebetween an extended position relative to the outer cannula, in which thesupporting portion is positioned within the interior of the balloon, anda retracted position relative to the outer cannula, in which thesupporting portion is positioned outside the interior of the balloon,wherein the inner cannula is slidably coupled to the outer cannula sothat the supporting portion is movable between the retracted positionand the extended position relative to the interior of the balloon, andwherein at least one of the inner and outer cannulas is mounted to thedelivery device, wherein the inner cannula is mounted to the deliverydevice, and the proximal end of the outer cannula is slidably coupled tothe inner cannula; and first and second lock rings mounted to the innercannula, the first and second lock rings limiting slidable movement ofthe outer cannula between an extended cannula position relative to theinner cannula and a retracted cannula position relative to the innercannula, respectively.
 3. The device for separating tissue layers ofclaim 2, further comprising:a sleeve mounted to the outer cannula, thesleeve having a detent extending inwardly toward the inner cannula; thefirst lock ring being configured to matingly engage the detent to lockthe inner and outer cannulas with the outer cannula in the retractedcannula position relative to the inner cannula.
 4. The device forseparating tissue layers of claim 3, further comprising:an elastomericmember coupled to the sleeve and contacting the inner cannula, theelastomeric member forming a substantially fluid tight seal between thesleeve and the inner cannula.
 5. A device for separating tissue layers,comprising:a delivery device having an inflation port; a balloon havingan interior; a fluid path fluidly coupling the inflation port and theinterior of the balloon; an outer cannula having a distal end and aproximal end, the balloon being mounted to the distal end of the outercannula; and an inner cannula at least partially disposed within theouter cannula, the inner cannula having a supporting portion movablebetween an extended position relative to the outer cannula, in which thesupporting portion is positioned within the interior of the balloon, anda retracted position relative to the outer cannula, in which thesupporting portion is positioned outside the interior of the balloon,wherein the inner cannula is slidably coupled to the outer cannula sothat the supporting portion is movable between the retracted positionand the extended position relative to the interior of the balloon, andwherein at least one of the inner and outer cannulas is mounted to thedelivery device, wherein:the inner cannula has a longitudinal axis andis mounted to the delivery device; and the proximal end of the outercannula is mounted to the delivery device, the outer cannula having acontracting portion between the distal and proximal ends, thecontracting portion changing a longitudinal length of the outer cannulain a direction of the longitudinal axis when the supporting portionmoves from the extended position to the retracted position.
 6. Thedevice for separating tissue layers of claim 5, wherein:the contractingportion of the outer cannula includes a number of longitudinallyextending segments.
 7. The device for separating tissue layers of claim5, wherein:at least a portion of the fluid path is housed within aninterior of the inner cannula.
 8. A device for separating tissue layers,comprising:a delivery device having an inflation port; an outer cannulahaving a distal end and being mounted to the delivery device; aninflatable balloon having an interior and being mounted to the distalend of the outer cannula; a fluid path fluidly coupling the inflationport and the interior of the balloon for inflating the balloon; aninsert having an inner cannula attached thereto, the insert beingslidably coupled to the delivery device between a retracted position andan extended position, a portion of the inner cannula being housed withinthe outer cannula when the insert is in the retracted position and theportion of the inner cannula extending beyond the distal end of theouter cannula when the insert is in the extended position, the inserthaving an opening adapted to receive an endoscope, and the outer cannulahaving a proximal end slidably coupled to the inner cannula; and firstand second lock rings mounted to the inner cannula, the first and secondlock rings limiting slidable movement of the outer cannula between anextended cannula position relative to the inner cannula and a retractedcannula position relative to the inner cannula, respectively.
 9. Amethod of separating tissue layers in a patient comprising the stepsof:(a) providing a delivery device, a balloon, a fluid path, an outercannula, and an inner cannula slidably disposed at least partiallywithin the outer cannula, wherein the inner cannula is attached to thedelivery device, wherein the inner cannula has a supporting portion, thedelivery device has an inflation port, the fluid path fluidly couples aninterior of the balloon to the inflation port, and the outer cannula isslidably coupled to the inner cannula, the outer and inner cannulasbeing slidably coupled to one another between an extended position inwhich the supporting portion extends into the interior of the balloon,and a retracted position in which the supporting portion is housedwithin the outer cannula; (b) inserting the balloon into the patientbetween said tissue layers; (c) inflating the balloon through theinflation port and the fluid path, the supporting portion providingsupport for the balloon during inflation, (d) removing the supportingportion from the interior of the balloon by sliding the outer cannulafrom the extended position to the retracted position; and (e) lockingthe outer cannula in the extended position during step (c).
 10. A methodof separating tissue layers in a patient, comprising the steps of:(a)providing a delivery device, a balloon, a fluid path, an outer cannula,an inner cannula slidably disposed at least partially within the outercannula, and an insert slidably coupled to the delivery device, whereinthe outer cannula is attached to the delivery device, the inner cannulahas a supporting portion, the delivery device has an inflation port, thefluid path fluidly couples an interior of the balloon to the inflationport, the supporting portion of the inner cannula is positioned withinthe interior of the balloon, and the insert has the inner cannulaattached thereto; (b) inserting the balloon into the patient betweensaid tissue layers; (c) inflating the balloon through the inflation portand the fluid path, the supporting portion providing support for theballoon during inflation; (d) removing the supporting portion from theinterior of the balloon by sliding at least one of the outer cannula andthe inner cannula relative to another of the inner cannula and the outercannula; (e) after step (d), inserting an endoscope into the interior ofthe balloon; locking the insert to the delivery device before initiatingstep (c); and unlocking the insert from the delivery device after step(c) but before step (d).
 11. A method of separating tissue layers in apatient, comprising the steps of:(a) providing a delivery device, aballoon, a fluid path, an outer cannula, an inner cannula slidablydisposed at least partially within the outer cannula, and an insertslidably coupled to the delivery device, wherein the outer cannula isattached to the delivery device, the inner cannula has a supportingportion, the delivery device has an inflation port, the fluid pathfluidly couples an interior of the balloon to the inflation port, thesupporting portion of the inner cannula is positioned within theinterior of the balloon, and the insert has the inner cannula attachedthereto; (b) inserting the balloon into the patient between said tissuelayers; (c) inflating the balloon through the inflation port and thefluid path, the supporting portion providing support for the balloonduring inflation; (d) removing the supporting portion from the interiorof the balloon by sliding at least one of the outer cannula and theinner cannula relative to another of the inner cannula and the outercannula; (e) inserting an endoscope through an opening in the insertinto the interior of the balloon; and (f) locking the endoscope to theinsert.
 12. The method of separating tissue layers in a patient of claim11, wherein:the removing step is carried out by sliding the insert to aretracted position after the endoscope locking step, at least a part ofthe supporting portion being housed within the outer cannula when in theretracted position.
 13. A method of separating tissue layers in apatient comprising the steps of:(a) providing a delivery device, aballoon, a fluid path, an outer cannula, an inner cannula slidablydisposed at least partially within the outer cannula, wherein at leastone of the outer cannula and the inner cannula is attached to thedelivery device, wherein the inner cannula has a supporting portion, thedelivery device has an inflation port, the fluid path fluidly couples aninterior of the balloon to the inflation port, and the supportingportion is positioned within the interior of the balloon; (b) insertingthe balloon into the patient between said tissue layers; (c) inflatingthe balloon through the inflation port and the fluid path, thesupporting portion providing support for the balloon during inflation;and (d) removing the supporting portion from the interior of the balloonby sliding at least one of the outer cannula and the inner cannularelative to another of the inner cannula and the outer cannula,wherein:step (a) is carried out by providing the inner cannula and theouter cannula to be mounted to the delivery device and the balloon to bemounted to the outer cannula, the outer cannula having a contractingportion which is movable between an extended position, in which thesupporting portion extends into the interior of the balloon, and aretracted position, in which the supporting portion is housed within theouter cannula.
 14. The method of separating tissue layers in a patientof claim 13, further comprising the step of:contracting the contractingportion from the extended position to the retracted position afterinitiating step (c).